639187458064 has 15 divisors (see below), whose sum is σ = 1238431896093. Its totient is φ = 319592130048.

The previous prime is 639187458061. The next prime is 639187458067. The reversal of 639187458064 is 460854781936.

It is a happy number.

The square root of 639187458064 is 799492.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (639187458061) and next prime (639187458067).

It can be written as a sum of positive squares in only one way, i.e., 638369040400 + 818417664 = 798980^2 + 28608^2 .

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639187457993 and 639187458011.

It is not an unprimeable number, because it can be changed into a prime (639187458061) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3098032 + ... + 3297904.

Almost surely, 2^639187458064 is an apocalyptic number.

639187458064 is the 799492-nd square number.

It is an amenable number.

639187458064 is a deficient number, since it is larger than the sum of its proper divisors (599244438029).

639187458064 is an frugal number, since it uses more digits than its factorization.

639187458064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399754 (or 199875 counting only the distinct ones).

The product of its (nonzero) digits is 34836480, while the sum is 61.

The spelling of 639187458064 in words is "six hundred thirty-nine billion, one hundred eighty-seven million, four hundred fifty-eight thousand, sixty-four".