66860380309 has 2 divisors, whose sum is σ = 66860380310. Its totient is φ = 66860380308.

The previous prime is 66860380297. The next prime is 66860380319. The reversal of 66860380309 is 90308306866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66386099025 + 474281284 = 257655^2 + 21778^2 .

It is a cyclic number.

It is not a de Polignac number, because 66860380309 - 2³⁵ = 32500641941 is a prime.

It is a super-2 number, since 2×66860380309² (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 (66860380319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33430190154 + 33430190155.

It is an arithmetic number, because the mean of its divisors is an integer number (33430190155).

Almost surely, 2^66860380309 is an apocalyptic number.

It is an amenable number.

66860380309 is a deficient number, since it is larger than the sum of its proper divisors (1).

66860380309 is an equidigital number, since it uses as much as digits as its factorization.

66860380309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1119744, while the sum is 49.

The spelling of 66860380309 in words is "sixty-six billion, eight hundred sixty million, three hundred eighty thousand, three hundred nine".