63910721951 has 4 divisors (see below), whose sum is σ = 63997205400. Its totient is φ = 63824238504.

The previous prime is 63910721947. The next prime is 63910722049. The reversal of 63910721951 is 15912701936.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 63910721951 - 2² = 63910721947 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (63915721951) 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, 43240616 + ... + 43242093.

It is an arithmetic number, because the mean of its divisors is an integer number (15999301350).

Almost surely, 2^63910721951 is an apocalyptic number.

63910721951 is a deficient number, since it is larger than the sum of its proper divisors (86483449).

63910721951 is an equidigital number, since it uses as much as digits as its factorization.

63910721951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86483448.

The product of its (nonzero) digits is 102060, while the sum is 44.

The spelling of 63910721951 in words is "sixty-three billion, nine hundred ten million, seven hundred twenty-one thousand, nine hundred fifty-one".