21908964 has 96 divisors (see below), whose sum is σ = 64576512. Its totient is φ = 5616000.

The previous prime is 21908959. The next prime is 21908987. The reversal of 21908964 is 46980912.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 120954 + ... + 121134.

It is an arithmetic number, because the mean of its divisors is an integer number (672672).

Almost surely, 2^21908964 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21908964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32288256).

21908964 is an abundant number, since it is smaller than the sum of its proper divisors (42667548).

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

21908964 is a wasteful number, since it uses less digits than its factorization.

21908964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 21908964 is about 4680.7012295168. The cubic root of 21908964 is about 279.8169041067.

The spelling of 21908964 in words is "twenty-one million, nine hundred eight thousand, nine hundred sixty-four".