390639893 has 4 divisors (see below), whose sum is σ = 446445600. Its totient is φ = 334834188.

The previous prime is 390639883. The next prime is 390639919. The reversal of 390639893 is 398936093.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 390639893 - 2⁴ = 390639877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (390639803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27902843 + ... + 27902856.

It is an arithmetic number, because the mean of its divisors is an integer number (111611400).

Almost surely, 2^390639893 is an apocalyptic number.

It is an amenable number.

390639893 is a deficient number, since it is larger than the sum of its proper divisors (55805707).

390639893 is an equidigital number, since it uses as much as digits as its factorization.

390639893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55805706.

The product of its (nonzero) digits is 944784, while the sum is 50.

The square root of 390639893 is about 19764.6121388708. The cubic root of 390639893 is about 731.0137245463.

The spelling of 390639893 in words is "three hundred ninety million, six hundred thirty-nine thousand, eight hundred ninety-three".