399976815 has 32 divisors (see below), whose sum is σ = 746956800. Its totient is φ = 178953984.

The previous prime is 399976813. The next prime is 399976879. The reversal of 399976815 is 518679993.

It is not a de Polignac number, because 399976815 - 2¹ = 399976813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399976813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35590 + ... + 45459.

It is an arithmetic number, because the mean of its divisors is an integer number (23342400).

Almost surely, 2^399976815 is an apocalyptic number.

399976815 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

399976815 is a deficient number, since it is larger than the sum of its proper divisors (346979985).

399976815 is a wasteful number, since it uses less digits than its factorization.

399976815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81111.

The product of its digits is 3674160, while the sum is 57.

The square root of 399976815 is about 19999.4203666006. The cubic root of 399976815 is about 736.7920637413.

The spelling of 399976815 in words is "three hundred ninety-nine million, nine hundred seventy-six thousand, eight hundred fifteen".