51031664065 has 4 divisors (see below), whose sum is σ = 61237996884. Its totient is φ = 40825331248.

The previous prime is 51031664063. The next prime is 51031664087. The reversal of 51031664065 is 56046613015.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7343975809 + 43687688256 = 85697^2 + 209016^2 .

It is a cyclic number.

It is not a de Polignac number, because 51031664065 - 2¹ = 51031664063 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51031664063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5103166402 + ... + 5103166411.

It is an arithmetic number, because the mean of its divisors is an integer number (15309499221).

Almost surely, 2^51031664065 is an apocalyptic number.

It is an amenable number.

51031664065 is a deficient number, since it is larger than the sum of its proper divisors (10206332819).

51031664065 is a wasteful number, since it uses less digits than its factorization.

51031664065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10206332818.

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 51031664065 in words is "fifty-one billion, thirty-one million, six hundred sixty-four thousand, sixty-five".