531981 has 32 divisors (see below), whose sum is σ = 892800. Its totient is φ = 311040.

The previous prime is 531977. The next prime is 531983. The reversal of 531981 is 189135.

531981 is nontrivially palindromic in base 5.

It is not a de Polignac number, because 531981 - 2² = 531977 is a prime.

It is a super-2 number, since 2×531981² = 566007568722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 531981.

It is not an unprimeable number, because it can be changed into a prime (531983) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8691 + ... + 8751.

It is an arithmetic number, because the mean of its divisors is an integer number (27900).

2⁵³¹⁹⁸¹ is an apocalyptic number.

531981 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

531981 is a deficient number, since it is larger than the sum of its proper divisors (360819).

531981 is a wasteful number, since it uses less digits than its factorization.

531981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 100 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 531981 is about 729.3702763343. The cubic root of 531981 is about 81.0274255553.

The spelling of 531981 in words is "five hundred thirty-one thousand, nine hundred eighty-one".