66656423521513 has 4 divisors (see below), whose sum is σ = 76178769738880. Its totient is φ = 57134077304148.

The previous prime is 66656423521487. The next prime is 66656423521531. The reversal of 66656423521513 is 31512532465666.

It is a happy number.

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 66656423521513 - 2¹³ = 66656423513321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66656423527513) 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, 4761173108673 + ... + 4761173108686.

It is an arithmetic number, because the mean of its divisors is an integer number (19044692434720).

Almost surely, 2^{66656423521513} is an apocalyptic number.

It is an amenable number.

66656423521513 is a deficient number, since it is larger than the sum of its proper divisors (9522346217367).

66656423521513 is an equidigital number, since it uses as much as digits as its factorization.

66656423521513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9522346217366.

The product of its digits is 23328000, while the sum is 55.

The spelling of 66656423521513 in words is "sixty-six trillion, six hundred fifty-six billion, four hundred twenty-three million, five hundred twenty-one thousand, five hundred thirteen".