21904960 has 168 divisors, whose sum is σ = 66714624. Its totient is φ = 6773760.

The previous prime is 21904951. The next prime is 21904963. The reversal of 21904960 is 6940912.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21904963) 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 23 ways as a sum of consecutive naturals, for example, 172417 + ... + 172543.

Almost surely, 2^21904960 is an apocalyptic number.

21904960 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 21904960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33357312).

21904960 is an abundant number, since it is smaller than the sum of its proper divisors (44809664).

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

21904960 is a wasteful number, since it uses less digits than its factorization.

21904960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21904960 is about 4680.2734962820. The cubic root of 21904960 is about 279.7998569725.

The spelling of 21904960 in words is "twenty-one million, nine hundred four thousand, nine hundred sixty".