399823657 has 4 divisors (see below), whose sum is σ = 399893760. Its totient is φ = 399753556.

The previous prime is 399823603. The next prime is 399823687. The reversal of 399823657 is 756328993.

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 399823657 - 2²⁷ = 265605929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399823687) 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, 25657 + ... + 38182.

It is an arithmetic number, because the mean of its divisors is an integer number (99973440).

Almost surely, 2^399823657 is an apocalyptic number.

It is an amenable number.

399823657 is a deficient number, since it is larger than the sum of its proper divisors (70103).

399823657 is an equidigital number, since it uses as much as digits as its factorization.

399823657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70102.

The product of its digits is 2449440, while the sum is 52.

The square root of 399823657 is about 19995.5909390045. The cubic root of 399823657 is about 736.6980082851.

The spelling of 399823657 in words is "three hundred ninety-nine million, eight hundred twenty-three thousand, six hundred fifty-seven".