51131531 has 4 divisors (see below), whose sum is σ = 55779864. Its totient is φ = 46483200.

The previous prime is 51131501. The next prime is 51131537. The reversal of 51131531 is 13513115.

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 51131531 - 2¹⁰ = 51130507 is a prime.

It is a super-2 number, since 2×51131531² = 5228866924807922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51131537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2324150 + ... + 2324171.

It is an arithmetic number, because the mean of its divisors is an integer number (13944966).

Almost surely, 2^51131531 is an apocalyptic number.

51131531 is a deficient number, since it is larger than the sum of its proper divisors (4648333).

51131531 is a wasteful number, since it uses less digits than its factorization.

51131531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4648332.

The product of its digits is 225, while the sum is 20.

The square root of 51131531 is about 7150.6315105730. The cubic root of 51131531 is about 371.1615094409.

Adding to 51131531 its reverse (13513115), we get a palindrome (64644646).

The spelling of 51131531 in words is "fifty-one million, one hundred thirty-one thousand, five hundred thirty-one".