51531 has 8 divisors (see below), whose sum is σ = 69840. Its totient is φ = 33792.

The previous prime is 51521. The next prime is 51539. The reversal of 51531 is 13515.

51531 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-51531 is a prime.

It is a super-2 number, since 2×51531² = 5310887922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 51531.

It is not an unprimeable number, because it can be changed into a prime (51539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 171 + ... + 363.

It is an arithmetic number, because the mean of its divisors is an integer number (8730).

2⁵¹⁵³¹ is an apocalyptic number.

51531 is a deficient number, since it is larger than the sum of its proper divisors (18309).

51531 is a wasteful number, since it uses less digits than its factorization.

51531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285.

The product of its digits is 75, while the sum is 15.

The square root of 51531 is about 227.0044052436. The cubic root of 51531 is about 37.2125579062.

The spelling of 51531 in words is "fifty-one thousand, five hundred thirty-one".