639974121784 has 32 divisors (see below), whose sum is σ = 1200799041120. Its totient is φ = 319761149056.

The previous prime is 639974121781. The next prime is 639974121803. The reversal of 639974121784 is 487121479936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639974121781) 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, 119999982 + ... + 120005314.

It is an arithmetic number, because the mean of its divisors is an integer number (37524970035).

Almost surely, 2^639974121784 is an apocalyptic number.

It is an amenable number.

639974121784 is a deficient number, since it is larger than the sum of its proper divisors (560824919336).

639974121784 is a wasteful number, since it uses less digits than its factorization.

639974121784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13119 (or 13115 counting only the distinct ones).

The product of its digits is 18289152, while the sum is 61.

The spelling of 639974121784 in words is "six hundred thirty-nine billion, nine hundred seventy-four million, one hundred twenty-one thousand, seven hundred eighty-four".