51894997721 has 8 divisors (see below), whose sum is σ = 59331462144. Its totient is φ = 44464256640.

The previous prime is 51894997639. The next prime is 51894997723. The reversal of 51894997721 is 12779949815.

51894997721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51894997721 - 2¹⁰ = 51894996697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51894997723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1411385 + ... + 1447686.

It is an arithmetic number, because the mean of its divisors is an integer number (7416432768).

Almost surely, 2^51894997721 is an apocalyptic number.

It is an amenable number.

51894997721 is a deficient number, since it is larger than the sum of its proper divisors (7436464423).

51894997721 is a wasteful number, since it uses less digits than its factorization.

51894997721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2861671.

The product of its digits is 11430720, while the sum is 62.

The spelling of 51894997721 in words is "fifty-one billion, eight hundred ninety-four million, nine hundred ninety-seven thousand, seven hundred twenty-one".