639000921789 has 24 divisors (see below), whose sum is σ = 1013491664640. Its totient is φ = 400941752256.

The previous prime is 639000921781. The next prime is 639000921799. The reversal of 639000921789 is 987129000936.

It is not a de Polignac number, because 639000921789 - 2³ = 639000921781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639000921781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77338029 + ... + 77346290.

It is an arithmetic number, because the mean of its divisors is an integer number (42228819360).

Almost surely, 2^639000921789 is an apocalyptic number.

It is an amenable number.

639000921789 is a deficient number, since it is larger than the sum of its proper divisors (374490742851).

639000921789 is a wasteful number, since it uses less digits than its factorization.

639000921789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154684351 (or 154684339 counting only the distinct ones).

The product of its (nonzero) digits is 1469664, while the sum is 54.

The spelling of 639000921789 in words is "six hundred thirty-nine billion, nine hundred twenty-one thousand, seven hundred eighty-nine".