391239023 has 4 divisors (see below), whose sum is σ = 447130320. Its totient is φ = 335347728.

The previous prime is 391239019. The next prime is 391239031. The reversal of 391239023 is 320932193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 320932193 = 593 ⋅541201.

It is a cyclic number.

It is not a de Polignac number, because 391239023 - 2² = 391239019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391239053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27945638 + ... + 27945651.

It is an arithmetic number, because the mean of its divisors is an integer number (111782580).

Almost surely, 2^391239023 is an apocalyptic number.

391239023 is a deficient number, since it is larger than the sum of its proper divisors (55891297).

391239023 is an equidigital number, since it uses as much as digits as its factorization.

391239023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55891296.

The product of its (nonzero) digits is 8748, while the sum is 32.

The square root of 391239023 is about 19779.7629662238. The cubic root of 391239023 is about 731.3872557218.

The spelling of 391239023 in words is "three hundred ninety-one million, two hundred thirty-nine thousand, twenty-three".