21235872 has 48 divisors (see below), whose sum is σ = 63709632. Its totient is φ = 6067200.

The previous prime is 21235861. The next prime is 21235883. The reversal of 21235872 is 27853212.

It is an interprime number because it is at equal distance from previous prime (21235861) and next prime (21235883).

It is a tau number, because it is divible by the number of its divisors (48).

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, 15129 + ... + 16472.

It is an arithmetic number, because the mean of its divisors is an integer number (1327284).

Almost surely, 2^21235872 is an apocalyptic number.

It is an amenable number.

21235872 is an abundant number, since it is smaller than the sum of its proper divisors (42473760).

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

21235872 is a wasteful number, since it uses less digits than its factorization.

21235872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31621 (or 31613 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21235872 is about 4608.2395771053. The cubic root of 21235872 is about 276.9215154708.

The spelling of 21235872 in words is "twenty-one million, two hundred thirty-five thousand, eight hundred seventy-two".