646989638 has 16 divisors (see below), whose sum is σ = 1037751264. Its totient is φ = 301449600.

The previous prime is 646989613. The next prime is 646989641. The reversal of 646989638 is 836989646.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90770 + ... + 97637.

It is an arithmetic number, because the mean of its divisors is an integer number (64859454).

Almost surely, 2^646989638 is an apocalyptic number.

646989638 is a deficient number, since it is larger than the sum of its proper divisors (390761626).

646989638 is a wasteful number, since it uses less digits than its factorization.

646989638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188527.

The product of its digits is 13436928, while the sum is 59.

The square root of 646989638 is about 25435.9909970105. The cubic root of 646989638 is about 864.8997569469.

The spelling of 646989638 in words is "six hundred forty-six million, nine hundred eighty-nine thousand, six hundred thirty-eight".