639450019456 has 16 divisors (see below), whose sum is σ = 1273904335890. Its totient is φ = 319725009664.

The previous prime is 639450019441. The next prime is 639450019489. The reversal of 639450019456 is 654910054936.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 551430997056 + 88019022400 = 742584^2 + 296680^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2497851511 + ... + 2497851766.

Almost surely, 2^639450019456 is an apocalyptic number.

It is an amenable number.

639450019456 is a deficient number, since it is larger than the sum of its proper divisors (634454316434).

639450019456 is an equidigital number, since it uses as much as digits as its factorization.

639450019456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4995703291 (or 4995703279 counting only the distinct ones).

The product of its (nonzero) digits is 3499200, while the sum is 52.

The spelling of 639450019456 in words is "six hundred thirty-nine billion, four hundred fifty million, nineteen thousand, four hundred fifty-six".