531691 has 4 divisors (see below), whose sum is σ = 554832. Its totient is φ = 508552.

The previous prime is 531689. The next prime is 531701. The reversal of 531691 is 196135.

531691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 196135 = 5 ⋅39227.

It is a cyclic number.

It is not a de Polignac number, because 531691 - 2¹ = 531689 is a prime.

It is a d-powerful number, because it can be written as 5 + 3³ + 6³ + 1 + 9⁶ + 1 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (531611) 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, 11536 + ... + 11581.

It is an arithmetic number, because the mean of its divisors is an integer number (138708).

531691 is a Friedman number, since it can be written as 9^6+5^3*(1+1), using all its digits and the basic arithmetic operations.

2⁵³¹⁶⁹¹ is an apocalyptic number.

531691 is a deficient number, since it is larger than the sum of its proper divisors (23141).

531691 is a wasteful number, since it uses less digits than its factorization.

531691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23140.

The product of its digits is 810, while the sum is 25.

The square root of 531691 is about 729.1714476034. The cubic root of 531691 is about 81.0126993247.

The spelling of 531691 in words is "five hundred thirty-one thousand, six hundred ninety-one".