66513244534561 has 4 divisors (see below), whose sum is σ = 72559903128624. Its totient is φ = 60466585940500.

The previous prime is 66513244534553. The next prime is 66513244534613. The reversal of 66513244534561 is 16543544231566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66513244534561 - 2³ = 66513244534553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66513244534861) 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, 3023329297015 + ... + 3023329297036.

It is an arithmetic number, because the mean of its divisors is an integer number (18139975782156).

Almost surely, 2^{66513244534561} is an apocalyptic number.

It is an amenable number.

66513244534561 is a deficient number, since it is larger than the sum of its proper divisors (6046658594063).

66513244534561 is a wasteful number, since it uses less digits than its factorization.

66513244534561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6046658594062.

The product of its digits is 31104000, while the sum is 55.

The spelling of 66513244534561 in words is "sixty-six trillion, five hundred thirteen billion, two hundred forty-four million, five hundred thirty-four thousand, five hundred sixty-one".