63776956681 has 3 divisors (see below), whose sum is σ = 63777209223. Its totient is φ = 63776704140.

The previous prime is 63776956643. The next prime is 63776956723. The reversal of 63776956681 is 18665967736.

The square root of 63776956681 is 252541.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1206937081 + 62570019600 = 34741^2 + 250140^2 .

It is not a de Polignac number, because 63776956681 - 2¹⁵ = 63776923913 is a prime.

It is a super-2 number, since 2×63776956681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63776957681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 126271 + ... + 378811.

It is an arithmetic number, because the mean of its divisors is an integer number (21259069741).

Almost surely, 2^63776956681 is an apocalyptic number.

63776956681 is the 252541-st square number.

63776956681 is the 126271-st centered octagonal number.

It is an amenable number.

63776956681 is a deficient number, since it is larger than the sum of its proper divisors (252542).

63776956681 is an frugal number, since it uses more digits than its factorization.

63776956681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 505082 (or 252541 counting only the distinct ones).

The product of its digits is 68584320, while the sum is 64.

Multiplying 63776956681 by its sum of digits (64), we get a square (4081725227584 = 2020328²).

The spelling of 63776956681 in words is "sixty-three billion, seven hundred seventy-six million, nine hundred fifty-six thousand, six hundred eighty-one".