21908704 has 12 divisors (see below), whose sum is σ = 43132824. Its totient is φ = 10954336.

The previous prime is 21908701. The next prime is 21908713. The reversal of 21908704 is 40780912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21908701) 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 as a sum of consecutive naturals, namely, 342292 + ... + 342355.

It is an arithmetic number, because the mean of its divisors is an integer number (3594402).

Almost surely, 2^21908704 is an apocalyptic number.

It is an amenable number.

21908704 is a deficient number, since it is larger than the sum of its proper divisors (21224120).

21908704 is an equidigital number, since it uses as much as digits as its factorization.

21908704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684657 (or 684649 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21908704 is about 4680.6734558181. The cubic root of 21908704 is about 279.8157972130.

The spelling of 21908704 in words is "twenty-one million, nine hundred eight thousand, seven hundred four".