231644394 has 64 divisors (see below), whose sum is σ = 525571200. Its totient is φ = 75613824.

The previous prime is 231644381. The next prime is 231644401. The reversal of 231644394 is 493446132.

It is a happy number.

231644394 is a `hidden beast` number, since 2 + 3 + 1 + 644 + 3 + 9 + 4 = 666.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 754389 + ... + 754695.

It is an arithmetic number, because the mean of its divisors is an integer number (8212050).

Almost surely, 2^231644394 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231644394, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (262785600).

231644394 is an abundant number, since it is smaller than the sum of its proper divisors (293926806).

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

231644394 is a wasteful number, since it uses less digits than its factorization.

231644394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564 (or 558 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 231644394 is about 15219.8683962773. The cubic root of 231644394 is about 614.1492579592.

The spelling of 231644394 in words is "two hundred thirty-one million, six hundred forty-four thousand, three hundred ninety-four".