664560713721 has 16 divisors (see below), whose sum is σ = 900246037824. Its totient is φ = 435999473664.

The previous prime is 664560713689. The next prime is 664560713743. The reversal of 664560713721 is 127317065466.

It is a happy number.

It is not a de Polignac number, because 664560713721 - 2⁵ = 664560713689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664560713321) 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, 5128456 + ... + 5256441.

It is an arithmetic number, because the mean of its divisors is an integer number (56265377364).

Almost surely, 2^664560713721 is an apocalyptic number.

It is an amenable number.

664560713721 is a deficient number, since it is larger than the sum of its proper divisors (235685324103).

664560713721 is a wasteful number, since it uses less digits than its factorization.

664560713721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10385240.

The product of its (nonzero) digits is 1270080, while the sum is 48.

The spelling of 664560713721 in words is "six hundred sixty-four billion, five hundred sixty million, seven hundred thirteen thousand, seven hundred twenty-one".