31223231 has 8 divisors (see below), whose sum is σ = 34710144. Its totient is φ = 27891360.

The previous prime is 31223219. The next prime is 31223239. The reversal of 31223231 is 13232213.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31223231 - 2¹⁸ = 30961087 is a prime.

It is a super-2 number, since 2×31223231² = 1949780308158722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31223239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38336 + ... + 39141.

It is an arithmetic number, because the mean of its divisors is an integer number (4338768).

Almost surely, 2^31223231 is an apocalyptic number.

31223231 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

31223231 is a deficient number, since it is larger than the sum of its proper divisors (3486913).

31223231 is a wasteful number, since it uses less digits than its factorization.

31223231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77521.

The product of its digits is 216, while the sum is 17.

The square root of 31223231 is about 5587.7751386397. The cubic root of 31223231 is about 314.8902985767.

Adding to 31223231 its reverse (13232213), we get a palindrome (44455444).

The spelling of 31223231 in words is "thirty-one million, two hundred twenty-three thousand, two hundred thirty-one".