21613960 has 16 divisors (see below), whose sum is σ = 48631500. Its totient is φ = 8645568.

The previous prime is 21613931. The next prime is 21613973. The reversal of 21613960 is 6931612.

It can be written as a sum of positive squares in 2 ways, for example, as 18438436 + 3175524 = 4294^2 + 1782^2 .

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 3 ways as a sum of consecutive naturals, for example, 270135 + ... + 270214.

Almost surely, 2^21613960 is an apocalyptic number.

21613960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21613960 is an abundant number, since it is smaller than the sum of its proper divisors (27017540).

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

21613960 is a wasteful number, since it uses less digits than its factorization.

21613960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540360 (or 540356 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21613960 is about 4649.0816297415. The cubic root of 21613960 is about 278.5553139296. Note that the first 3 decimals are identical.

The spelling of 21613960 in words is "twenty-one million, six hundred thirteen thousand, nine hundred sixty".