531391 has 4 divisors (see below), whose sum is σ = 607312. Its totient is φ = 455472.

The previous prime is 531383. The next prime is 531457. The reversal of 531391 is 193135.

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 531391 - 2³ = 531383 is a prime.

It is a Duffinian number.

531391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (531331) 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, 37950 + ... + 37963.

It is an arithmetic number, because the mean of its divisors is an integer number (151828).

531391 is a Friedman number, since it can be written as 9^(3+3)-51+1, using all its digits and the basic arithmetic operations.

2⁵³¹³⁹¹ is an apocalyptic number.

531391 is a deficient number, since it is larger than the sum of its proper divisors (75921).

531391 is an equidigital number, since it uses as much as digits as its factorization.

531391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75920.

The product of its digits is 405, while the sum is 22.

The square root of 531391 is about 728.9657056405. The cubic root of 531391 is about 80.9974596572.

It can be divided in two parts, 53 and 1391, that added together give a square (1444 = 38²).

The spelling of 531391 in words is "five hundred thirty-one thousand, three hundred ninety-one".