51279921 has 81 divisors (see below), whose sum is σ = 97863129. Its totient is φ = 25779600.

The previous prime is 51279913. The next prime is 51279929. The reversal of 51279921 is 12997215.

The square root of 51279921 is 7161.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (51279913) and next prime (51279929).

It is not a de Polignac number, because 51279921 - 2³ = 51279913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51279929) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1654176 + ... + 1654206.

Almost surely, 2^51279921 is an apocalyptic number.

51279921 is the 7161-st square number.

51279921 is the 3581-st centered octagonal number.

It is an amenable number.

51279921 is a deficient number, since it is larger than the sum of its proper divisors (46583208).

51279921 is a wasteful number, since it uses less digits than its factorization.

51279921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104 (or 52 counting only the distinct ones).

The product of its digits is 11340, while the sum is 36.

The cubic root of 51279921 is about 371.5202147987.

Multiplying 51279921 by its sum of digits (36), we get a square (1846077156 = 42966²).

It can be divided in two parts, 51 and 279921, that added together give a palindrome (279972).

The spelling of 51279921 in words is "fifty-one million, two hundred seventy-nine thousand, nine hundred twenty-one".