891231031 has 4 divisors (see below), whose sum is σ = 891305064. Its totient is φ = 891157000.

The previous prime is 891231023. The next prime is 891231073. The reversal of 891231031 is 130132198.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 891231031 - 2³ = 891231023 is a prime.

It is a super-2 number, since 2×891231031² = 1588585501234645922, 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 (891231931) 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, 14320 + ... + 44581.

It is an arithmetic number, because the mean of its divisors is an integer number (222826266).

Almost surely, 2^891231031 is an apocalyptic number.

891231031 is a deficient number, since it is larger than the sum of its proper divisors (74033).

891231031 is a wasteful number, since it uses less digits than its factorization.

891231031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74032.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 891231031 is about 29853.4927772279. The cubic root of 891231031 is about 962.3434612686.

The spelling of 891231031 in words is "eight hundred ninety-one million, two hundred thirty-one thousand, thirty-one".