63969721 has 4 divisors (see below), whose sum is σ = 64051792. Its totient is φ = 63887652.

The previous prime is 63969683. The next prime is 63969727. The reversal of 63969721 is 12796936.

63969721 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 a cyclic number.

It is not a de Polignac number, because 63969721 - 2¹⁹ = 63445433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63969727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39855 + ... + 41428.

It is an arithmetic number, because the mean of its divisors is an integer number (16012948).

Almost surely, 2^63969721 is an apocalyptic number.

It is an amenable number.

63969721 is a deficient number, since it is larger than the sum of its proper divisors (82071).

63969721 is an equidigital number, since it uses as much as digits as its factorization.

63969721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82070.

The product of its digits is 122472, while the sum is 43.

The square root of 63969721 is about 7998.1073386146. The cubic root of 63969721 is about 399.9369087993.

The spelling of 63969721 in words is "sixty-three million, nine hundred sixty-nine thousand, seven hundred twenty-one".