191431864 has 64 divisors (see below), whose sum is σ = 398240640. Its totient is φ = 85726080.

The previous prime is 191431841. The next prime is 191431909. The reversal of 191431864 is 468134191.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

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, 578179 + ... + 578509.

It is an arithmetic number, because the mean of its divisors is an integer number (6222510).

Almost surely, 2^191431864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191431864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199120320).

191431864 is an abundant number, since it is smaller than the sum of its proper divisors (206808776).

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

191431864 is a wasteful number, since it uses less digits than its factorization.

191431864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500 (or 496 counting only the distinct ones).

The product of its digits is 20736, while the sum is 37.

The square root of 191431864 is about 13835.8904303265. The cubic root of 191431864 is about 576.3302424007.

The spelling of 191431864 in words is "one hundred ninety-one million, four hundred thirty-one thousand, eight hundred sixty-four".