399656593 has 6 divisors (see below), whose sum is σ = 464906706. Its totient is φ = 342562752.

The previous prime is 399656581. The next prime is 399656617. The reversal of 399656593 is 395656993.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 318872449 + 80784144 = 17857^2 + 8988^2 .

It is a de Polignac number, because none of the positive numbers 2^k-399656593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399656693) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4078080 + ... + 4078177.

It is an arithmetic number, because the mean of its divisors is an integer number (77484451).

Almost surely, 2^399656593 is an apocalyptic number.

It is an amenable number.

399656593 is a deficient number, since it is larger than the sum of its proper divisors (65250113).

399656593 is an equidigital number, since it uses as much as digits as its factorization.

399656593 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8156271 (or 8156264 counting only the distinct ones).

The product of its digits is 5904900, while the sum is 55.

The square root of 399656593 is about 19991.4129815779. The cubic root of 399656593 is about 736.5953856579.

The spelling of 399656593 in words is "three hundred ninety-nine million, six hundred fifty-six thousand, five hundred ninety-three".