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21402040 = 23511127383
BaseRepresentation
bin101000110100…
…1000110111000
31111021100002011
41101221012320
520434331130
62042415304
7346625422
oct121510670
944240064
1021402040
1111098740
127201534
13458463a
142bb1812
151d2b52a
hex14691b8

21402040 has 64 divisors (see below), whose sum is σ = 53084160. Its totient is φ = 7701120.

The previous prime is 21402023. The next prime is 21402047. The reversal of 21402040 is 4020412.

It is a self number, because there is not a number n which added to its sum of digits gives 21402040.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55689 + ... + 56071.

It is an arithmetic number, because the mean of its divisors is an integer number (829440).

Almost surely, 221402040 is an apocalyptic number.

21402040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21402040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26542080).

21402040 is an abundant number, since it is smaller than the sum of its proper divisors (31682120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21402040 is a wasteful number, since it uses less digits than its factorization.

21402040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532 (or 528 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 21402040 is about 4626.2338894613. The cubic root of 21402040 is about 277.6419315609.

Adding to 21402040 its reverse (4020412), we get a palindrome (25422452).

The spelling of 21402040 in words is "twenty-one million, four hundred two thousand, forty".

Divisors: 1 2 4 5 8 10 11 20 22 40 44 55 88 110 127 220 254 383 440 508 635 766 1016 1270 1397 1532 1915 2540 2794 3064 3830 4213 5080 5588 6985 7660 8426 11176 13970 15320 16852 21065 27940 33704 42130 48641 55880 84260 97282 168520 194564 243205 389128 486410 535051 972820 1070102 1945640 2140204 2675255 4280408 5350510 10701020 21402040