64724002561 has 4 divisors (see below), whose sum is σ = 64727353300. Its totient is φ = 64720651824.

The previous prime is 64724002513. The next prime is 64724002597. The reversal of 64724002561 is 16520042746.

64724002561 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.

It can be written as a sum of positive squares in 2 ways, for example, as 13963912561 + 50760090000 = 118169^2 + 225300^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64724002561 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64724002561.

It is not an unprimeable number, because it can be changed into a prime (64724002261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1646226 + ... + 1685083.

It is an arithmetic number, because the mean of its divisors is an integer number (16181838325).

Almost surely, 2^64724002561 is an apocalyptic number.

It is an amenable number.

64724002561 is a deficient number, since it is larger than the sum of its proper divisors (3350739).

64724002561 is a wasteful number, since it uses less digits than its factorization.

64724002561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3350738.

The product of its (nonzero) digits is 80640, while the sum is 37.

The spelling of 64724002561 in words is "sixty-four billion, seven hundred twenty-four million, two thousand, five hundred sixty-one".