997531 has 4 divisors (see below), whose sum is σ = 1001032. Its totient is φ = 994032.

The previous prime is 997511. The next prime is 997541. The reversal of 997531 is 135799.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 997531 - 2⁹ = 997019 is a prime.

It is a super-2 number, since 2×997531² = 1990136191922, which contains 22 as substring.

It is a Duffinian number.

997531 is a lucky number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (997511) 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, 1281 + ... + 1906.

It is an arithmetic number, because the mean of its divisors is an integer number (250258).

2⁹⁹⁷⁵³¹ is an apocalyptic number.

997531 is a deficient number, since it is larger than the sum of its proper divisors (3501).

997531 is a wasteful number, since it uses less digits than its factorization.

997531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3500.

The product of its digits is 8505, while the sum is 34.

The square root of 997531 is about 998.7647370627. The cubic root of 997531 is about 99.9176321740.

The spelling of 997531 in words is "nine hundred ninety-seven thousand, five hundred thirty-one".