981531 has 8 divisors (see below), whose sum is σ = 1454160. Its totient is φ = 654336.

The previous prime is 981527. The next prime is 981569. The reversal of 981531 is 135189.

It is not a de Polignac number, because 981531 - 2² = 981527 is a prime.

It is a super-2 number, since 2×981531² = 1926806207922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 36353 = 981531 / (9 + 8 + 1 + 5 + 3 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 981495 and 981504.

It is not an unprimeable number, because it can be changed into a prime (981731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18150 + ... + 18203.

It is an arithmetic number, because the mean of its divisors is an integer number (181770).

2⁹⁸¹⁵³¹ is an apocalyptic number.

981531 is a deficient number, since it is larger than the sum of its proper divisors (472629).

981531 is a wasteful number, since it uses less digits than its factorization.

981531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36362 (or 36356 counting only the distinct ones).

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

The square root of 981531 is about 990.7224636597. The cubic root of 981531 is about 99.3805372493.

The spelling of 981531 in words is "nine hundred eighty-one thousand, five hundred thirty-one".