320878391 has 2 divisors, whose sum is σ = 320878392. Its totient is φ = 320878390.

The previous prime is 320878387. The next prime is 320878399. The reversal of 320878391 is 193878023.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 320878391 - 2² = 320878387 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (320878399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160439195 + 160439196.

It is an arithmetic number, because the mean of its divisors is an integer number (160439196).

Almost surely, 2^320878391 is an apocalyptic number.

320878391 is a deficient number, since it is larger than the sum of its proper divisors (1).

320878391 is an equidigital number, since it uses as much as digits as its factorization.

320878391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 320878391 is about 17913.0787694355. The cubic root of 320878391 is about 684.6156516843.

The spelling of 320878391 in words is "three hundred twenty million, eight hundred seventy-eight thousand, three hundred ninety-one".