399639636 has 48 divisors (see below), whose sum is σ = 1130297280. Its totient is φ = 121102560.

The previous prime is 399639623. The next prime is 399639641. The reversal of 399639636 is 636936993.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167011 + ... + 169386.

It is an arithmetic number, because the mean of its divisors is an integer number (23547860).

Almost surely, 2^399639636 is an apocalyptic number.

399639636 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

399639636 is an abundant number, since it is smaller than the sum of its proper divisors (730657644).

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

399639636 is a wasteful number, since it uses less digits than its factorization.

399639636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336421 (or 336413 counting only the distinct ones).

The product of its digits is 4251528, while the sum is 54.

The square root of 399639636 is about 19990.9888699884. The cubic root of 399639636 is about 736.5849678602.

The spelling of 399639636 in words is "three hundred ninety-nine million, six hundred thirty-nine thousand, six hundred thirty-six".