399822642 has 30 divisors (see below), whose sum is σ = 896469519. Its totient is φ = 133189380.

The previous prime is 399822613. The next prime is 399822649. The reversal of 399822642 is 246228993.

It can be written as a sum of positive squares in only one way, i.e., 199911321 + 199911321 = 14139^2 + 14139^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=14139.

It is not an unprimeable number, because it can be changed into a prime (399822649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 253717 + ... + 255287.

Almost surely, 2^399822642 is an apocalyptic number.

399822642 is an abundant number, since it is smaller than the sum of its proper divisors (496646877).

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

399822642 is an frugal number, since it uses more digits than its factorization.

399822642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3156 (or 1576 counting only the distinct ones).

The product of its digits is 373248, while the sum is 45.

The square root of 399822642 is about 19995.5655583932. The cubic root of 399822642 is about 736.6973848860.

Multiplying 399822642 by its product of digits (373248), we get a square (149233001481216 = 12216096²).

It can be divided in two parts, 39982 and 2642, that added together give a palindrome (42624).

The spelling of 399822642 in words is "three hundred ninety-nine million, eight hundred twenty-two thousand, six hundred forty-two".