63913721 has 4 divisors (see below), whose sum is σ = 64401744. Its totient is φ = 63425700.

The previous prime is 63913691. The next prime is 63913741. The reversal of 63913721 is 12731936.

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 not a de Polignac number, because 63913721 - 2⁶ = 63913657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63913741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 243815 + ... + 244076.

It is an arithmetic number, because the mean of its divisors is an integer number (16100436).

Almost surely, 2^63913721 is an apocalyptic number.

It is an amenable number.

63913721 is a deficient number, since it is larger than the sum of its proper divisors (488023).

63913721 is a wasteful number, since it uses less digits than its factorization.

63913721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488022.

The product of its digits is 6804, while the sum is 32.

The square root of 63913721 is about 7994.6057438751. The cubic root of 63913721 is about 399.8201712495.

The spelling of 63913721 in words is "sixty-three million, nine hundred thirteen thousand, seven hundred twenty-one".