21908136 has 16 divisors (see below), whose sum is σ = 54770400. Its totient is φ = 7302704.

The previous prime is 21908119. The next prime is 21908141. The reversal of 21908136 is 63180912.

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, 456396 + ... + 456443.

It is an arithmetic number, because the mean of its divisors is an integer number (3423150).

Almost surely, 2^21908136 is an apocalyptic number.

It is an amenable number.

21908136 is an abundant number, since it is smaller than the sum of its proper divisors (32862264).

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

21908136 is a wasteful number, since it uses less digits than its factorization.

21908136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912848 (or 912844 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21908136 is about 4680.6127803953. The cubic root of 21908136 is about 279.8133790455.

The spelling of 21908136 in words is "twenty-one million, nine hundred eight thousand, one hundred thirty-six".