51039394561 has 3 divisors (see below), whose sum is σ = 51039620481. Its totient is φ = 51039168642.

The previous prime is 51039394541. The next prime is 51039394583. The reversal of 51039394561 is 16549393015.

The square root of 51039394561 is 225919.

It is a perfect power (a square), and thus also a powerful number.

51039394561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 51039394561 - 2⁵ = 51039394529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51039394501) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 112960 + ... + 338878.

It is an arithmetic number, because the mean of its divisors is an integer number (17013206827).

Almost surely, 2^51039394561 is an apocalyptic number.

51039394561 is the 225919-th square number.

51039394561 is the 112960-th centered octagonal number.

It is an amenable number.

51039394561 is a deficient number, since it is larger than the sum of its proper divisors (225920).

51039394561 is an frugal number, since it uses more digits than its factorization.

51039394561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451838 (or 225919 counting only the distinct ones).

The product of its (nonzero) digits is 437400, while the sum is 46.

The spelling of 51039394561 in words is "fifty-one billion, thirty-nine million, three hundred ninety-four thousand, five hundred sixty-one".