21172938 has 32 divisors (see below), whose sum is σ = 44390400. Its totient is φ = 6724080.

The previous prime is 21172927. The next prime is 21172961. The reversal of 21172938 is 83927112.

It is a junction number, because it is equal to n+sod(n) for n = 21172899 and 21172908.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11613 + ... + 13311.

It is an arithmetic number, because the mean of its divisors is an integer number (1387200).

Almost surely, 2^21172938 is an apocalyptic number.

21172938 is an abundant number, since it is smaller than the sum of its proper divisors (23217462).

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

21172938 is a wasteful number, since it uses less digits than its factorization.

21172938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1802.

The product of its digits is 6048, while the sum is 33.

The square root of 21172938 is about 4601.4060894470. The cubic root of 21172938 is about 276.6476859932.

The spelling of 21172938 in words is "twenty-one million, one hundred seventy-two thousand, nine hundred thirty-eight".