21240908 has 12 divisors (see below), whose sum is σ = 40031040. Its totient is φ = 9803472.

The previous prime is 21240907. The next prime is 21240913. The reversal of 21240908 is 80904212.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (21240907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 204188 + ... + 204291.

It is an arithmetic number, because the mean of its divisors is an integer number (3335920).

Almost surely, 2^21240908 is an apocalyptic number.

It is an amenable number.

21240908 is a deficient number, since it is larger than the sum of its proper divisors (18790132).

21240908 is a wasteful number, since it uses less digits than its factorization.

21240908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408496 (or 408494 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21240908 is about 4608.7859572777. The cubic root of 21240908 is about 276.9434040080.

The spelling of 21240908 in words is "twenty-one million, two hundred forty thousand, nine hundred eight".