639751993 has 8 divisors (see below), whose sum is σ = 645264576. Its totient is φ = 634249200.

The previous prime is 639751967. The next prime is 639752023. The reversal of 639751993 is 399157936.

639751993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 639751993 - 2²⁵ = 606197561 is a prime.

It is a super-2 number, since 2×639751993² = 818565225094944098, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 639751993.

It is not an unprimeable number, because it can be changed into a prime (639751093) 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, 193948 + ... + 197218.

It is an arithmetic number, because the mean of its divisors is an integer number (80658072).

Almost surely, 2^639751993 is an apocalyptic number.

It is an amenable number.

639751993 is a deficient number, since it is larger than the sum of its proper divisors (5512583).

639751993 is a wasteful number, since it uses less digits than its factorization.

639751993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4895.

The product of its digits is 1377810, while the sum is 52.

The square root of 639751993 is about 25293.3191376695. The cubic root of 639751993 is about 861.6625460301.

The spelling of 639751993 in words is "six hundred thirty-nine million, seven hundred fifty-one thousand, nine hundred ninety-three".