639309894 has 16 divisors (see below), whose sum is σ = 1282417968. Its totient is φ = 212470272.

The previous prime is 639309893. The next prime is 639309917. The reversal of 639309894 is 498903936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639309893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156067 + ... + 160110.

It is an arithmetic number, because the mean of its divisors is an integer number (80151123).

Almost surely, 2^639309894 is an apocalyptic number.

639309894 is an abundant number, since it is smaller than the sum of its proper divisors (643108074).

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

639309894 is a wasteful number, since it uses less digits than its factorization.

639309894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316519.

The product of its (nonzero) digits is 1259712, while the sum is 51.

The square root of 639309894 is about 25284.5781851310. The cubic root of 639309894 is about 861.4640170496.

The spelling of 639309894 in words is "six hundred thirty-nine million, three hundred nine thousand, eight hundred ninety-four".