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21530460 = 2235751263
BaseRepresentation
bin101001000100…
…0011101011100
31111111212020110
41102020131130
521002433320
62045250020
7351002010
oct122103534
944455213
1021530460
1111176176
127263910
1345cac23
142c06540
151d545e0
hex148875c

21530460 has 48 divisors (see below), whose sum is σ = 68898816. Its totient is φ = 4921152.

The previous prime is 21530459. The next prime is 21530471. The reversal of 21530460 is 6403512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

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, 25212 + ... + 26051.

It is an arithmetic number, because the mean of its divisors is an integer number (1435392).

Almost surely, 221530460 is an apocalyptic number.

21530460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21530460 is an abundant number, since it is smaller than the sum of its proper divisors (47368356).

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

21530460 is a wasteful number, since it uses less digits than its factorization.

21530460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51282 (or 51280 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21530460 is about 4640.0926714884. The cubic root of 21530460 is about 278.1961419659.

Adding to 21530460 its reverse (6403512), we get a palindrome (27933972).

The spelling of 21530460 in words is "twenty-one million, five hundred thirty thousand, four hundred sixty".

Divisors: 1 2 3 4 5 6 7 10 12 14 15 20 21 28 30 35 42 60 70 84 105 140 210 420 51263 102526 153789 205052 256315 307578 358841 512630 615156 717682 768945 1025260 1076523 1435364 1537890 1794205 2153046 3075780 3588410 4306092 5382615 7176820 10765230 21530460