66638652313 has 4 divisors (see below), whose sum is σ = 66649453668. Its totient is φ = 66627850960.

The previous prime is 66638652299. The next prime is 66638652341. The reversal of 66638652313 is 31325683666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31325683666 = 2 ⋅15662841833.

It can be written as a sum of positive squares in 2 ways, for example, as 2696932624 + 63941719689 = 51932^2 + 252867^2 .

It is a cyclic number.

It is not a de Polignac number, because 66638652313 - 2⁵ = 66638652281 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66638652413) 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, 5391418 + ... + 5403763.

It is an arithmetic number, because the mean of its divisors is an integer number (16662363417).

Almost surely, 2^66638652313 is an apocalyptic number.

It is an amenable number.

66638652313 is a deficient number, since it is larger than the sum of its proper divisors (10801355).

66638652313 is a wasteful number, since it uses less digits than its factorization.

66638652313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10801354.

The product of its digits is 2799360, while the sum is 49.

The spelling of 66638652313 in words is "sixty-six billion, six hundred thirty-eight million, six hundred fifty-two thousand, three hundred thirteen".