51131555 has 16 divisors (see below), whose sum is σ = 63949824. Its totient is φ = 39203040.

The previous prime is 51131543. The next prime is 51131557. The reversal of 51131555 is 55513115.

51131555 = 695² + 696² + ... + 787².

It is not a de Polignac number, because 51131555 - 2⁴ = 51131539 is a prime.

It is a super-2 number, since 2×51131555² = 5228871833436050, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51131557) 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 15 ways as a sum of consecutive naturals, for example, 15044 + ... + 18126.

It is an arithmetic number, because the mean of its divisors is an integer number (3996864).

Almost surely, 2^51131555 is an apocalyptic number.

51131555 is a deficient number, since it is larger than the sum of its proper divisors (12818269).

51131555 is a wasteful number, since it uses less digits than its factorization.

51131555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3226.

The product of its digits is 1875, while the sum is 26.

The square root of 51131555 is about 7150.6331887463. The cubic root of 51131555 is about 371.1615675125.

The spelling of 51131555 in words is "fifty-one million, one hundred thirty-one thousand, five hundred fifty-five".