31138231 has 4 divisors (see below), whose sum is σ = 31167864. Its totient is φ = 31108600.

The previous prime is 31138213. The next prime is 31138249. The reversal of 31138231 is 13283113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13283113 = 173 ⋅76781.

It is an interprime number because it is at equal distance from previous prime (31138213) and next prime (31138249).

It is a cyclic number.

It is not a de Polignac number, because 31138231 - 2⁷ = 31138103 is a prime.

It is a super-2 number, since 2×31138231² = 1939178859618722, 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 (31138531) 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, 13180 + ... + 15361.

It is an arithmetic number, because the mean of its divisors is an integer number (7791966).

Almost surely, 2^31138231 is an apocalyptic number.

31138231 is a deficient number, since it is larger than the sum of its proper divisors (29633).

31138231 is a wasteful number, since it uses less digits than its factorization.

31138231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29632.

The product of its digits is 432, while the sum is 22.

The square root of 31138231 is about 5580.1640656884. The cubic root of 31138231 is about 314.6042935768.

The spelling of 31138231 in words is "thirty-one million, one hundred thirty-eight thousand, two hundred thirty-one".