66716823601 has 2 divisors, whose sum is σ = 66716823602. Its totient is φ = 66716823600.

The previous prime is 66716823599. The next prime is 66716823617. The reversal of 66716823601 is 10632861766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53121030400 + 13595793201 = 230480^2 + 116601^2 .

It is a cyclic number.

It is not a de Polignac number, because 66716823601 - 2¹ = 66716823599 is a prime.

It is a super-2 number, since 2×66716823601² (a number of 22 digits) contains 22 as substring.

Together with 66716823599, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (66716823661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33358411800 + 33358411801.

It is an arithmetic number, because the mean of its divisors is an integer number (33358411801).

Almost surely, 2^66716823601 is an apocalyptic number.

It is an amenable number.

66716823601 is a deficient number, since it is larger than the sum of its proper divisors (1).

66716823601 is an equidigital number, since it uses as much as digits as its factorization.

66716823601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 435456, while the sum is 46.

The spelling of 66716823601 in words is "sixty-six billion, seven hundred sixteen million, eight hundred twenty-three thousand, six hundred one".