51131537644 has 24 divisors (see below), whose sum is σ = 97659168768. Its totient is φ = 23231033040.

The previous prime is 51131537603. The next prime is 51131537663. The reversal of 51131537644 is 44673513115.

It is a happy number.

It is a super-2 number, since 2×51131537644² (a number of 22 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 51131537597 and 51131537606.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166164 + ... + 360379.

It is an arithmetic number, because the mean of its divisors is an integer number (4069132032).

Almost surely, 2^51131537644 is an apocalyptic number.

It is an amenable number.

51131537644 is a deficient number, since it is larger than the sum of its proper divisors (46527631124).

51131537644 is a wasteful number, since it uses less digits than its factorization.

51131537644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528765 (or 528763 counting only the distinct ones).

The product of its digits is 151200, while the sum is 40.

The spelling of 51131537644 in words is "fifty-one billion, one hundred thirty-one million, five hundred thirty-seven thousand, six hundred forty-four".