63991815752 has 36 divisors (see below), whose sum is σ = 127481978715. Its totient is φ = 30108071680.

The previous prime is 63991815691. The next prime is 63991815763. The reversal of 63991815752 is 25751819936.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 5 ways, for example, as 60532729156 + 3459086596 = 246034^2 + 58814^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=178874.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 12160802 + ... + 12166062.

Almost surely, 2^63991815752 is an apocalyptic number.

It is an amenable number.

63991815752 is a deficient number, since it is larger than the sum of its proper divisors (63490162963).

63991815752 is an frugal number, since it uses more digits than its factorization.

63991815752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10562 (or 5280 counting only the distinct ones).

The product of its digits is 4082400, while the sum is 56.

The spelling of 63991815752 in words is "sixty-three billion, nine hundred ninety-one million, eight hundred fifteen thousand, seven hundred fifty-two".