66666672889 has 2 divisors, whose sum is σ = 66666672890. Its totient is φ = 66666672888.

The previous prime is 66666672871. The next prime is 66666672899. The reversal of 66666672889 is 98827666666.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58370560000 + 8296112889 = 241600^2 + 91083^2 .

It is a cyclic number.

It is not a de Polignac number, because 66666672889 - 2²¹ = 66664575737 is a prime.

It is not a weakly prime, because it can be changed into another prime (66666672829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333336444 + 33333336445.

It is an arithmetic number, because the mean of its divisors is an integer number (33333336445).

Almost surely, 2^66666672889 is an apocalyptic number.

It is an amenable number.

66666672889 is a deficient number, since it is larger than the sum of its proper divisors (1).

66666672889 is an equidigital number, since it uses as much as digits as its factorization.

66666672889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 376233984, while the sum is 70.

The spelling of 66666672889 in words is "sixty-six billion, six hundred sixty-six million, six hundred seventy-two thousand, eight hundred eighty-nine".