21038172 has 12 divisors (see below), whose sum is σ = 49089096. Its totient is φ = 7012720.

The previous prime is 21038153. The next prime is 21038179. The reversal of 21038172 is 27183012.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21038172² = 885209362203168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21038179) 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, 876579 + ... + 876602.

It is an arithmetic number, because the mean of its divisors is an integer number (4090758).

Almost surely, 2^21038172 is an apocalyptic number.

It is an amenable number.

21038172 is an abundant number, since it is smaller than the sum of its proper divisors (28050924).

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

21038172 is a wasteful number, since it uses less digits than its factorization.

21038172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1753188 (or 1753186 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21038172 is about 4586.7387106745. The cubic root of 21038172 is about 276.0594809841.

The spelling of 21038172 in words is "twenty-one million, thirty-eight thousand, one hundred seventy-two".