21983040 has 168 divisors, whose sum is σ = 80238600. Its totient is φ = 5505024.

The previous prime is 21983029. The next prime is 21983041. The reversal of 21983040 is 4038912.

It can be written as a sum of positive squares in 4 ways, for example, as 5531904 + 16451136 = 2352^2 + 4056^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21982995 and 21983013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21983041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48736 + ... + 49184.

Almost surely, 2^21983040 is an apocalyptic number.

21983040 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 21983040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40119300).

21983040 is an abundant number, since it is smaller than the sum of its proper divisors (58255560).

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

21983040 is a wasteful number, since it uses less digits than its factorization.

21983040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489 (or 476 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21983040 is about 4688.6074691746. The cubic root of 21983040 is about 280.1319106350.

The spelling of 21983040 in words is "twenty-one million, nine hundred eighty-three thousand, forty".