51115491840 has 160 divisors (see below), whose sum is σ = 186754296960. Its totient is φ = 11683528704.

The previous prime is 51115491827. The next prime is 51115491859. The reversal of 51115491840 is 4819451115.

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×51115491840² (a number of 22 digits) contains 22 as substring.

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, 421645 + ... + 529164.

It is an arithmetic number, because the mean of its divisors is an integer number (1167214356).

Almost surely, 2^51115491840 is an apocalyptic number.

It is an amenable number.

51115491840 is an abundant number, since it is smaller than the sum of its proper divisors (135638805120).

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

51115491840 is an equidigital number, since it uses as much as digits as its factorization.

51115491840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950842 (or 950826 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 39.

The spelling of 51115491840 in words is "fifty-one billion, one hundred fifteen million, four hundred ninety-one thousand, eight hundred forty".