63963973921 has 3 divisors (see below), whose sum is σ = 63964226833. Its totient is φ = 63963721010.

The previous prime is 63963973877. The next prime is 63963973937. The reversal of 63963973921 is 12937936936.

The square root of 63963973921 is 252911.

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 is not a de Polignac number, because 63963973921 - 2⁷ = 63963973793 is a prime.

It is a super-2 number, since 2×63963973921² (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 (63963970921) 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, 126456 + ... + 379366.

Almost surely, 2^63963973921 is an apocalyptic number.

63963973921 is the 252911-st square number.

63963973921 is the 126456-th centered octagonal number.

It is an amenable number.

63963973921 is a deficient number, since it is larger than the sum of its proper divisors (252912).

63963973921 is an frugal number, since it uses more digits than its factorization.

63963973921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505822 (or 252911 counting only the distinct ones).

The product of its digits is 9920232, while the sum is 58.

The spelling of 63963973921 in words is "sixty-three billion, nine hundred sixty-three million, nine hundred seventy-three thousand, nine hundred twenty-one".