63771265721 has 4 divisors (see below), whose sum is σ = 66543929472. Its totient is φ = 60998601972.

The previous prime is 63771265697. The next prime is 63771265769. The reversal of 63771265721 is 12756217736.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63771265721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (63771265421) 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 3 ways as a sum of consecutive naturals, for example, 1386331841 + ... + 1386331886.

It is an arithmetic number, because the mean of its divisors is an integer number (16635982368).

Almost surely, 2^63771265721 is an apocalyptic number.

It is an amenable number.

63771265721 is a deficient number, since it is larger than the sum of its proper divisors (2772663751).

63771265721 is a wasteful number, since it uses less digits than its factorization.

63771265721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2772663750.

The product of its digits is 740880, while the sum is 47.

The spelling of 63771265721 in words is "sixty-three billion, seven hundred seventy-one million, two hundred sixty-five thousand, seven hundred twenty-one".