63974819721 has 4 divisors (see below), whose sum is σ = 85299759632. Its totient is φ = 42649879812.

The previous prime is 63974819681. The next prime is 63974819767. The reversal of 63974819721 is 12791847936.

It is a happy number.

63974819721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 63974819721 - 2⁷ = 63974819593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63974819621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10662469951 + ... + 10662469956.

It is an arithmetic number, because the mean of its divisors is an integer number (21324939908).

Almost surely, 2^63974819721 is an apocalyptic number.

It is an amenable number.

63974819721 is a deficient number, since it is larger than the sum of its proper divisors (21324939911).

63974819721 is a wasteful number, since it uses less digits than its factorization.

63974819721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21324939910.

The product of its digits is 4572288, while the sum is 57.

The spelling of 63974819721 in words is "sixty-three billion, nine hundred seventy-four million, eight hundred nineteen thousand, seven hundred twenty-one".