21723308 has 24 divisors (see below), whose sum is σ = 40251120. Its totient is φ = 10229760.

The previous prime is 21723307. The next prime is 21723311. The reversal of 21723308 is 80332712.

It is a super-2 number, since 2×21723308² = 943804220925728, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21723301) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 13928 + ... + 15408.

It is an arithmetic number, because the mean of its divisors is an integer number (1677130).

Almost surely, 2^21723308 is an apocalyptic number.

It is an amenable number.

21723308 is a deficient number, since it is larger than the sum of its proper divisors (18527812).

21723308 is a wasteful number, since it uses less digits than its factorization.

21723308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1697 (or 1695 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21723308 is about 4660.8269652498. The cubic root of 21723308 is about 279.0242738694.

The spelling of 21723308 in words is "twenty-one million, seven hundred twenty-three thousand, three hundred eight".