21431608 has 32 divisors (see below), whose sum is σ = 44064000. Its totient is φ = 9691360.

The previous prime is 21431593. The next prime is 21431623. The reversal of 21431608 is 80613412.

It is an interprime number because it is at equal distance from previous prime (21431593) and next prime (21431623).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20523 + ... + 21541.

It is an arithmetic number, because the mean of its divisors is an integer number (1377000).

Almost surely, 2^21431608 is an apocalyptic number.

It is an amenable number.

21431608 is an abundant number, since it is smaller than the sum of its proper divisors (22632392).

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

21431608 is a wasteful number, since it uses less digits than its factorization.

21431608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1275 (or 1271 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 21431608 is about 4629.4284744448. The cubic root of 21431608 is about 277.7697315121.

The spelling of 21431608 in words is "twenty-one million, four hundred thirty-one thousand, six hundred eight".