51988977861 has 4 divisors (see below), whose sum is σ = 69318637152. Its totient is φ = 34659318572.

The previous prime is 51988977853. The next prime is 51988977863. The reversal of 51988977861 is 16877988915.

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 51988977861 - 2³ = 51988977853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51988977863) 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, 8664829641 + ... + 8664829646.

It is an arithmetic number, because the mean of its divisors is an integer number (17329659288).

Almost surely, 2^51988977861 is an apocalyptic number.

It is an amenable number.

51988977861 is a deficient number, since it is larger than the sum of its proper divisors (17329659291).

51988977861 is a wasteful number, since it uses less digits than its factorization.

51988977861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17329659290.

The product of its digits is 60963840, while the sum is 69.

The spelling of 51988977861 in words is "fifty-one billion, nine hundred eighty-eight million, nine hundred seventy-seven thousand, eight hundred sixty-one".