639085217922 has 90 divisors (see below), whose sum is σ = 1447999539987. Its totient is φ = 210677967576.

The previous prime is 639085217917. The next prime is 639085217951. The reversal of 639085217922 is 229712580936.

639085217922 is a `hidden beast` number, since 6 + 3 + 90 + 8 + 521 + 7 + 9 + 22 = 666.

It can be written as a sum of positive squares in only one way, i.e., 319542608961 + 319542608961 = 565281^2 + 565281^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=565281.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1088730913 + ... + 1088731499.

Almost surely, 2^639085217922 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639085217922

639085217922 is an abundant number, since it is smaller than the sum of its proper divisors (808914322065).

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

639085217922 is an frugal number, since it uses more digits than its factorization.

639085217922 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1402 (or 699 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The spelling of 639085217922 in words is "six hundred thirty-nine billion, eighty-five million, two hundred seventeen thousand, nine hundred twenty-two".