21458172 has 24 divisors (see below), whose sum is σ = 52246656. Its totient is φ = 6841648.

The previous prime is 21458141. The next prime is 21458189. The reversal of 21458172 is 27185412.

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, 38598 + ... + 39149.

It is an arithmetic number, because the mean of its divisors is an integer number (2176944).

Almost surely, 2^21458172 is an apocalyptic number.

It is an amenable number.

21458172 is an abundant number, since it is smaller than the sum of its proper divisors (30788484).

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

21458172 is a wasteful number, since it uses less digits than its factorization.

21458172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77777 (or 77775 counting only the distinct ones).

The product of its digits is 4480, while the sum is 30.

The square root of 21458172 is about 4632.2966226268. The cubic root of 21458172 is about 277.8844472578.

The spelling of 21458172 in words is "twenty-one million, four hundred fifty-eight thousand, one hundred seventy-two".