320501991 has 8 divisors (see below), whose sum is σ = 434341744. Its totient is φ = 210165120.

The previous prime is 320501989. The next prime is 320502031. The reversal of 320501991 is 199105023.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 320501991 - 2¹ = 320501989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (320501921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 875506 + ... + 875871.

It is an arithmetic number, because the mean of its divisors is an integer number (54292718).

Almost surely, 2^320501991 is an apocalyptic number.

320501991 is a deficient number, since it is larger than the sum of its proper divisors (113839753).

320501991 is a wasteful number, since it uses less digits than its factorization.

320501991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1751441.

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 320501991 is about 17902.5693965978. The cubic root of 320501991 is about 684.3478553651.

The spelling of 320501991 in words is "three hundred twenty million, five hundred one thousand, nine hundred ninety-one".