51981372 has 48 divisors (see below), whose sum is σ = 136684800. Its totient is φ = 17080560.

The previous prime is 51981361. The next prime is 51981373. The reversal of 51981372 is 27318915.

51981372 is a `hidden beast` number, since 519 + 8 + 137 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51981373) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4279 + ... + 11057.

It is an arithmetic number, because the mean of its divisors is an integer number (2847600).

Almost surely, 2^51981372 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51981372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68342400).

51981372 is an abundant number, since it is smaller than the sum of its proper divisors (84703428).

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

51981372 is a wasteful number, since it uses less digits than its factorization.

51981372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6863 (or 6855 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 51981372 is about 7209.8108158259. The cubic root of 51981372 is about 373.2065403471.

The spelling of 51981372 in words is "fifty-one million, nine hundred eighty-one thousand, three hundred seventy-two".