399709538 has 18 divisors (see below), whose sum is σ = 611544843. Its totient is φ = 195938820.

The previous prime is 399709537. The next prime is 399709543. The reversal of 399709538 is 835907993.

It can be written as a sum of positive squares in only one way, i.e., 199854769 + 199854769 = 14137^2 + 14137^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=14137.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 399709538.

It is not an unprimeable number, because it can be changed into a prime (399709537) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1894253 + ... + 1894463.

Almost surely, 2^399709538 is an apocalyptic number.

399709538 is a deficient number, since it is larger than the sum of its proper divisors (211835305).

399709538 is an frugal number, since it uses more digits than its factorization.

399709538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 558 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 1837080, while the sum is 53.

The square root of 399709538 is about 19992.7371312684. The cubic root of 399709538 is about 736.6279113490.

The spelling of 399709538 in words is "three hundred ninety-nine million, seven hundred nine thousand, five hundred thirty-eight".