51166787927581 has 4 divisors (see below), whose sum is σ = 52817329473664. Its totient is φ = 49516246381500.

The previous prime is 51166787927561. The next prime is 51166787927599. The reversal of 51166787927581 is 18572978766115.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51166787927581 - 2⁹ = 51166787927069 is a prime.

It is a super-2 number, since 2×51166787927581² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51166787927561) 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, 825270772995 + ... + 825270773056.

It is an arithmetic number, because the mean of its divisors is an integer number (13204332368416).

Almost surely, 2^{51166787927581} is an apocalyptic number.

It is an amenable number.

51166787927581 is a deficient number, since it is larger than the sum of its proper divisors (1650541546083).

51166787927581 is a wasteful number, since it uses less digits than its factorization.

51166787927581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1650541546082.

The product of its digits is 355622400, while the sum is 73.

The spelling of 51166787927581 in words is "fifty-one trillion, one hundred sixty-six billion, seven hundred eighty-seven million, nine hundred twenty-seven thousand, five hundred eighty-one".