51931981944 has 96 divisors (see below), whose sum is σ = 145484951040. Its totient is φ = 16717780800.

The previous prime is 51931981943. The next prime is 51931981951. The reversal of 51931981944 is 44918913915.

It is a happy number.

51931981944 is a `hidden beast` number, since 519 + 3 + 1 + 9 + 81 + 9 + 44 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51931981943) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1072219 + ... + 1119605.

It is an arithmetic number, because the mean of its divisors is an integer number (1515468240).

Almost surely, 2^51931981944 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 51931981944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (72742475520).

51931981944 is an abundant number, since it is smaller than the sum of its proper divisors (93552969096).

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

51931981944 is a wasteful number, since it uses less digits than its factorization.

51931981944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47921 (or 47914 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 54.

The spelling of 51931981944 in words is "fifty-one billion, nine hundred thirty-one million, nine hundred eighty-one thousand, nine hundred forty-four".