399788865 has 80 divisors (see below), whose sum is σ = 845644800. Its totient is φ = 176826240.

The previous prime is 399788849. The next prime is 399788869. The reversal of 399788865 is 568887993.

It is not a de Polignac number, because 399788865 - 2⁴ = 399788849 is a prime.

It is a super-2 number, since 2×399788865² = 319662273155976450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (399788869) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 85611 + ... + 90159.

It is an arithmetic number, because the mean of its divisors is an integer number (10570560).

Almost surely, 2^399788865 is an apocalyptic number.

399788865 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

It is an amenable number.

399788865 is an abundant number, since it is smaller than the sum of its proper divisors (445855935).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399788865 is a wasteful number, since it uses less digits than its factorization.

399788865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4604 (or 4595 counting only the distinct ones).

The product of its digits is 26127360, while the sum is 63.

The square root of 399788865 is about 19994.7209282850. The cubic root of 399788865 is about 736.6766389137.

The spelling of 399788865 in words is "three hundred ninety-nine million, seven hundred eighty-eight thousand, eight hundred sixty-five".