51529988721 has 4 divisors (see below), whose sum is σ = 68706651632. Its totient is φ = 34353325812.

The previous prime is 51529988681. The next prime is 51529988723. The reversal of 51529988721 is 12788992515.

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 not a de Polignac number, because 51529988721 - 2¹⁹ = 51529464433 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51529988723) 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, 8588331451 + ... + 8588331456.

It is an arithmetic number, because the mean of its divisors is an integer number (17176662908).

Almost surely, 2^51529988721 is an apocalyptic number.

It is an amenable number.

51529988721 is a deficient number, since it is larger than the sum of its proper divisors (17176662911).

51529988721 is a wasteful number, since it uses less digits than its factorization.

51529988721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17176662910.

The product of its digits is 3628800, while the sum is 57.

The spelling of 51529988721 in words is "fifty-one billion, five hundred twenty-nine million, nine hundred eighty-eight thousand, seven hundred twenty-one".