51665943240 has 96 divisors (see below), whose sum is σ = 167945094720. Its totient is φ = 13775059584.

The previous prime is 51665943179. The next prime is 51665943247. The reversal of 51665943240 is 4234956615.

51665943240 is a `hidden beast` number, since 5 + 16 + 6 + 594 + 3 + 2 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (51665943247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2770989 + ... + 2789571.

It is an arithmetic number, because the mean of its divisors is an integer number (1749428070).

Almost surely, 2^51665943240 is an apocalyptic number.

It is an amenable number.

51665943240 is an abundant number, since it is smaller than the sum of its proper divisors (116279151480).

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

51665943240 is a wasteful number, since it uses less digits than its factorization.

51665943240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26323 (or 26316 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 51665943240 in words is "fifty-one billion, six hundred sixty-five million, nine hundred forty-three thousand, two hundred forty".