66681340079 has 2 divisors, whose sum is σ = 66681340080. Its totient is φ = 66681340078.

The previous prime is 66681340021. The next prime is 66681340111. The reversal of 66681340079 is 97004318666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66681340079 - 2²⁴ = 66664562863 is a prime.

It is a super-2 number, since 2×66681340079² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66683340079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33340670039 + 33340670040.

It is an arithmetic number, because the mean of its divisors is an integer number (33340670040).

Almost surely, 2^66681340079 is an apocalyptic number.

66681340079 is a deficient number, since it is larger than the sum of its proper divisors (1).

66681340079 is an equidigital number, since it uses as much as digits as its factorization.

66681340079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1306368, while the sum is 50.

The spelling of 66681340079 in words is "sixty-six billion, six hundred eighty-one million, three hundred forty thousand, seventy-nine".