51605617517 has 4 divisors (see below), whose sum is σ = 51735606876. Its totient is φ = 51475628160.

The previous prime is 51605617507. The next prime is 51605617579. The reversal of 51605617517 is 71571650615.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43963186276 + 7642431241 = 209674^2 + 87421^2 .

It is a cyclic number.

It is not a de Polignac number, because 51605617517 - 2¹⁶ = 51605551981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51605617507) 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, 64994084 + ... + 64994877.

It is an arithmetic number, because the mean of its divisors is an integer number (12933901719).

Almost surely, 2^51605617517 is an apocalyptic number.

It is an amenable number.

51605617517 is a deficient number, since it is larger than the sum of its proper divisors (129989359).

51605617517 is a wasteful number, since it uses less digits than its factorization.

51605617517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129989358.

The product of its (nonzero) digits is 220500, while the sum is 44.

The spelling of 51605617517 in words is "fifty-one billion, six hundred five million, six hundred seventeen thousand, five hundred seventeen".