51331 has 4 divisors (see below), whose sum is σ = 58672. Its totient is φ = 43992.

The previous prime is 51329. The next prime is 51341. The reversal of 51331 is 13315.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13315 = 5 ⋅2663.

It is a cyclic number.

It is not a de Polignac number, because 51331 - 2¹ = 51329 is a prime.

It is a super-2 number, since 2×51331² = 5269743122, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (51341) 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, 3660 + ... + 3673.

It is an arithmetic number, because the mean of its divisors is an integer number (14668).

2⁵¹³³¹ is an apocalyptic number.

51331 is a deficient number, since it is larger than the sum of its proper divisors (7341).

51331 is an equidigital number, since it uses as much as digits as its factorization.

51331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7340.

The product of its digits is 45, while the sum is 13.

The square root of 51331 is about 226.5634568945. The cubic root of 51331 is about 37.1643528715.

Adding to 51331 its reverse (13315), we get a palindrome (64646).

The spelling of 51331 in words is "fifty-one thousand, three hundred thirty-one".