639221694 has 48 divisors (see below), whose sum is σ = 1337212800. Its totient is φ = 203646816.

The previous prime is 639221689. The next prime is 639221699. The reversal of 639221694 is 496122936.

It is an interprime number because it is at equal distance from previous prime (639221689) and next prime (639221699).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639221699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 483967 + ... + 485285.

It is an arithmetic number, because the mean of its divisors is an integer number (27858600).

Almost surely, 2^639221694 is an apocalyptic number.

639221694 is an abundant number, since it is smaller than the sum of its proper divisors (697991106).

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

639221694 is a wasteful number, since it uses less digits than its factorization.

639221694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1457 (or 1420 counting only the distinct ones).

The product of its digits is 139968, while the sum is 42.

The square root of 639221694 is about 25282.8339788086. The cubic root of 639221694 is about 861.4243990065.

The spelling of 639221694 in words is "six hundred thirty-nine million, two hundred twenty-one thousand, six hundred ninety-four".