66620216513 has 4 divisors (see below), whose sum is σ = 67422869808. Its totient is φ = 65817563220.

The previous prime is 66620216491. The next prime is 66620216521. The reversal of 66620216513 is 31561202666.

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 66620216513 - 2¹⁸ = 66619954369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66620216413) 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, 401326523 + ... + 401326688.

It is an arithmetic number, because the mean of its divisors is an integer number (16855717452).

Almost surely, 2^66620216513 is an apocalyptic number.

It is an amenable number.

66620216513 is a deficient number, since it is larger than the sum of its proper divisors (802653295).

66620216513 is an equidigital number, since it uses as much as digits as its factorization.

66620216513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 802653294.

The product of its (nonzero) digits is 77760, while the sum is 38.

The spelling of 66620216513 in words is "sixty-six billion, six hundred twenty million, two hundred sixteen thousand, five hundred thirteen".