51381172816 has 20 divisors (see below), whose sum is σ = 100072237824. Its totient is φ = 25556079200.

The previous prime is 51381172813. The next prime is 51381172831. The reversal of 51381172816 is 61827118315.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51381172811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8403550 + ... + 8409661.

Almost surely, 2^51381172816 is an apocalyptic number.

It is an amenable number.

51381172816 is a deficient number, since it is larger than the sum of its proper divisors (48691065008).

51381172816 is a wasteful number, since it uses less digits than its factorization.

51381172816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16813410 (or 16813404 counting only the distinct ones).

The product of its digits is 80640, while the sum is 43.

The spelling of 51381172816 in words is "fifty-one billion, three hundred eighty-one million, one hundred seventy-two thousand, eight hundred sixteen".