51155111556 has 36 divisors (see below), whose sum is σ = 133767679500. Its totient is φ = 16463713728.

The previous prime is 51155111543. The next prime is 51155111593. The reversal of 51155111556 is 65511155115.

51155111556 is a `hidden beast` number, since 51 + 1 + 5 + 51 + 1 + 1 + 556 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 29013671556 + 22141440000 = 170334^2 + 148800^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×51155111556² (a number of 22 digits) contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 51155111556.

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, 24498531 + ... + 24500618.

It is an arithmetic number, because the mean of its divisors is an integer number (3715768875).

Almost surely, 2^51155111556 is an apocalyptic number.

It is an amenable number.

51155111556 is an abundant number, since it is smaller than the sum of its proper divisors (82612567944).

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

51155111556 is a wasteful number, since it uses less digits than its factorization.

51155111556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48999188 (or 48999183 counting only the distinct ones).

The product of its digits is 18750, while the sum is 36.

The spelling of 51155111556 in words is "fifty-one billion, one hundred fifty-five million, one hundred eleven thousand, five hundred fifty-six".