639979642164 has 48 divisors (see below), whose sum is σ = 1523035882368. Its totient is φ = 209084873088.

The previous prime is 639979642163. The next prime is 639979642171. The reversal of 639979642164 is 461246979936.

It is a happy number.

It is a super-3 number, since 3×639979642164³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 639979642095 and 639979642104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639979642163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94714 + ... + 1135310.

It is an arithmetic number, because the mean of its divisors is an integer number (31729914216).

Almost surely, 2^639979642164 is an apocalyptic number.

It is an amenable number.

639979642164 is an abundant number, since it is smaller than the sum of its proper divisors (883056240204).

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

639979642164 is a wasteful number, since it uses less digits than its factorization.

639979642164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041624 (or 1041622 counting only the distinct ones).

The product of its digits is 105815808, while the sum is 66.

The spelling of 639979642164 in words is "six hundred thirty-nine billion, nine hundred seventy-nine million, six hundred forty-two thousand, one hundred sixty-four".