51540344640 has 84 divisors (see below), whose sum is σ = 177277320324. Its totient is φ = 13744091136.

The previous prime is 51540344633. The next prime is 51540344659. The reversal of 51540344640 is 4644304515.

51540344640 is a `hidden beast` number, since 5 + 1 + 5 + 4 + 0 + 3 + 4 + 4 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 7762314816 + 43778029824 = 88104^2 + 209232^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 51540344595 and 51540344604.

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, 8945097 + ... + 8950856.

Almost surely, 2^51540344640 is an apocalyptic number.

It is an amenable number.

51540344640 is an abundant number, since it is smaller than the sum of its proper divisors (125736975684).

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

51540344640 is a wasteful number, since it uses less digits than its factorization.

51540344640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17895976 (or 17895963 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 36.

The spelling of 51540344640 in words is "fifty-one billion, five hundred forty million, three hundred forty-four thousand, six hundred forty".