399813406864 has 15 divisors (see below), whose sum is σ = 774643376217. Its totient is φ = 199905438816.

The previous prime is 399813406847. The next prime is 399813406873. The reversal of 399813406864 is 468604318993.

The square root of 399813406864 is 632308.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 137062848400 + 262750558464 = 370220^2 + 512592^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2450194 + ... + 2608270.

Almost surely, 2^399813406864 is an apocalyptic number.

399813406864 is the 632308-th square number.

It is an amenable number.

399813406864 is a deficient number, since it is larger than the sum of its proper divisors (374829969353).

399813406864 is an frugal number, since it uses more digits than its factorization.

399813406864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316162 (or 158079 counting only the distinct ones).

The product of its (nonzero) digits is 26873856, while the sum is 61.

The spelling of 399813406864 in words is "three hundred ninety-nine billion, eight hundred thirteen million, four hundred six thousand, eight hundred sixty-four".