21723908 has 12 divisors (see below), whose sum is σ = 38068800. Its totient is φ = 10847112.

The previous prime is 21723907. The next prime is 21723913. The reversal of 21723908 is 80932712.

It is not an unprimeable number, because it can be changed into a prime (21723907) 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, 8 + ... + 6591.

It is an arithmetic number, because the mean of its divisors is an integer number (3172400).

Almost surely, 2^21723908 is an apocalyptic number.

It is an amenable number.

21723908 is a deficient number, since it is larger than the sum of its proper divisors (16344892).

21723908 is a wasteful number, since it uses less digits than its factorization.

21723908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7426 (or 7424 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21723908 is about 4660.8913310653. The cubic root of 21723908 is about 279.0268427388.

The spelling of 21723908 in words is "twenty-one million, seven hundred twenty-three thousand, nine hundred eight".