99531 has 6 divisors (see below), whose sum is σ = 143780. Its totient is φ = 66348.

The previous prime is 99529. The next prime is 99551. The reversal of 99531 is 13599.

It is not a de Polignac number, because 99531 - 2¹ = 99529 is a prime.

It is a super-2 number, since 2×99531² = 19812839922, which contains 22 as substring.

It is a Duffinian number.

99531 is a lucky number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 99495 and 99504.

It is not an unprimeable number, because it can be changed into a prime (99551) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5521 + ... + 5538.

2⁹⁹⁵³¹ is an apocalyptic number.

99531 is a deficient number, since it is larger than the sum of its proper divisors (44249).

99531 is a wasteful number, since it uses less digits than its factorization.

99531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11065 (or 11062 counting only the distinct ones).

The product of its digits is 1215, while the sum is 27.

The square root of 99531 is about 315.4853403884. The cubic root of 99531 is about 46.3432110932.

It can be divided in two parts, 99 and 531, that added together give a triangular number (630 = T₃₅).

The spelling of 99531 in words is "ninety-nine thousand, five hundred thirty-one".