51978864 has 40 divisors (see below), whose sum is σ = 153462400. Its totient is φ = 14851008.

The previous prime is 51978863. The next prime is 51978869. The reversal of 51978864 is 46887915.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51978863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77014 + ... + 77685.

It is an arithmetic number, because the mean of its divisors is an integer number (3836560).

Almost surely, 2^51978864 is an apocalyptic number.

It is an amenable number.

51978864 is an abundant number, since it is smaller than the sum of its proper divisors (101483536).

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

51978864 is a wasteful number, since it uses less digits than its factorization.

51978864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154717 (or 154711 counting only the distinct ones).

The product of its digits is 483840, while the sum is 48.

The square root of 51978864 is about 7209.6368840601. The cubic root of 51978864 is about 373.2005380876.

The spelling of 51978864 in words is "fifty-one million, nine hundred seventy-eight thousand, eight hundred sixty-four".