51491066544431 has 4 divisors (see below), whose sum is σ = 51721968188352. Its totient is φ = 51260164900512.

The previous prime is 51491066544403. The next prime is 51491066544443. The reversal of 51491066544431 is 13444566019415.

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

It is a cyclic number.

It is not a de Polignac number, because 51491066544431 - 2¹⁰ = 51491066543407 is a prime.

It is a super-2 number, since 2×51491066544431² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51491066144431) 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, 115450821626 + ... + 115450822071.

It is an arithmetic number, because the mean of its divisors is an integer number (12930492047088).

Almost surely, 2^{51491066544431} is an apocalyptic number.

51491066544431 is a deficient number, since it is larger than the sum of its proper divisors (230901643921).

51491066544431 is a wasteful number, since it uses less digits than its factorization.

51491066544431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230901643920.

The product of its (nonzero) digits is 6220800, while the sum is 53.

The spelling of 51491066544431 in words is "fifty-one trillion, four hundred ninety-one billion, sixty-six million, five hundred forty-four thousand, four hundred thirty-one".