231091640 has 64 divisors (see below), whose sum is σ = 575134560. Its totient is φ = 83013120.

The previous prime is 231091579. The next prime is 231091657. The reversal of 231091640 is 46190132.

231091640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13235 + ... + 25245.

Almost surely, 2^231091640 is an apocalyptic number.

231091640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231091640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287567280).

231091640 is an abundant number, since it is smaller than the sum of its proper divisors (344042920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231091640 is a wasteful number, since it uses less digits than its factorization.

231091640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12072 (or 12068 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 231091640 is about 15201.6985893024. The cubic root of 231091640 is about 613.6603709043.

The spelling of 231091640 in words is "two hundred thirty-one million, ninety-one thousand, six hundred forty".