51521657440 has 96 divisors (see below), whose sum is σ = 135873593856. Its totient is φ = 18299420160.

The previous prime is 51521657413. The next prime is 51521657459. The reversal of 51521657440 is 4475612515.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 51521657393 and 51521657402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 264712 + ... + 416071.

It is an arithmetic number, because the mean of its divisors is an integer number (1415349936).

Almost surely, 2^51521657440 is an apocalyptic number.

It is an amenable number.

51521657440 is an abundant number, since it is smaller than the sum of its proper divisors (84351936416).

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

51521657440 is a wasteful number, since it uses less digits than its factorization.

51521657440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 680852 (or 680844 counting only the distinct ones).

The product of its (nonzero) digits is 168000, while the sum is 40.

The spelling of 51521657440 in words is "fifty-one billion, five hundred twenty-one million, six hundred fifty-seven thousand, four hundred forty".