64661356313 has 4 divisors (see below), whose sum is σ = 64669636020. Its totient is φ = 64653076608.

The previous prime is 64661356273. The next prime is 64661356321. The reversal of 64661356313 is 31365316646.

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 20998328464 + 43663027849 = 144908^2 + 208957^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64661356313 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (64661356343) 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, 4128128 + ... + 4143761.

It is an arithmetic number, because the mean of its divisors is an integer number (16167409005).

Almost surely, 2^64661356313 is an apocalyptic number.

It is an amenable number.

64661356313 is a deficient number, since it is larger than the sum of its proper divisors (8279707).

64661356313 is an equidigital number, since it uses as much as digits as its factorization.

64661356313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8279706.

The product of its digits is 699840, while the sum is 44.

The spelling of 64661356313 in words is "sixty-four billion, six hundred sixty-one million, three hundred fifty-six thousand, three hundred thirteen".