66624242681 has 2 divisors, whose sum is σ = 66624242682. Its totient is φ = 66624242680.

The previous prime is 66624242603. The next prime is 66624242723. The reversal of 66624242681 is 18624242666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66246523456 + 377719225 = 257384^2 + 19435^2 .

It is a cyclic number.

It is not a de Polignac number, because 66624242681 - 2³⁴ = 49444373497 is a prime.

It is a super-2 number, since 2×66624242681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66624232681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33312121340 + 33312121341.

It is an arithmetic number, because the mean of its divisors is an integer number (33312121341).

Almost surely, 2^66624242681 is an apocalyptic number.

It is an amenable number.

66624242681 is a deficient number, since it is larger than the sum of its proper divisors (1).

66624242681 is an equidigital number, since it uses as much as digits as its factorization.

66624242681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1327104, while the sum is 47.

The spelling of 66624242681 in words is "sixty-six billion, six hundred twenty-four million, two hundred forty-two thousand, six hundred eighty-one".