64993824721 has 16 divisors (see below), whose sum is σ = 77419184128. Its totient is φ = 53388493200.

The previous prime is 64993824713. The next prime is 64993824739. The reversal of 64993824721 is 12742839946.

It is not a de Polignac number, because 64993824721 - 2³ = 64993824713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64993824781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1431585 + ... + 1476286.

It is an arithmetic number, because the mean of its divisors is an integer number (4838699008).

Almost surely, 2^64993824721 is an apocalyptic number.

It is an amenable number.

64993824721 is a deficient number, since it is larger than the sum of its proper divisors (12425359407).

64993824721 is a wasteful number, since it uses less digits than its factorization.

64993824721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2908012.

The product of its digits is 5225472, while the sum is 55.

The spelling of 64993824721 in words is "sixty-four billion, nine hundred ninety-three million, eight hundred twenty-four thousand, seven hundred twenty-one".