51521639544 has 48 divisors (see below), whose sum is σ = 144705844920. Its totient is φ = 17173879200.

The previous prime is 51521639413. The next prime is 51521639573. The reversal of 51521639544 is 44593612515.

It is a happy number.

51521639544 is a `hidden beast` number, since 5 + 1 + 5 + 2 + 1 + 639 + 5 + 4 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 51521639544.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13249507 + ... + 13253394.

Almost surely, 2^51521639544 is an apocalyptic number.

51521639544 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is an amenable number.

51521639544 is an abundant number, since it is smaller than the sum of its proper divisors (93184205376).

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

51521639544 is a wasteful number, since it uses less digits than its factorization.

51521639544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26502922 (or 26502906 counting only the distinct ones).

The product of its digits is 648000, while the sum is 45.

The spelling of 51521639544 in words is "fifty-one billion, five hundred twenty-one million, six hundred thirty-nine thousand, five hundred forty-four".