6642665129 has 2 divisors, whose sum is σ = 6642665130. Its totient is φ = 6642665128.

The previous prime is 6642664981. The next prime is 6642665137. The reversal of 6642665129 is 9215662466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4405375129 + 2237290000 = 66373^2 + 47300^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6642665129 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (6642665189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3321332564 + 3321332565.

It is an arithmetic number, because the mean of its divisors is an integer number (3321332565).

Almost surely, 2^6642665129 is an apocalyptic number.

It is an amenable number.

6642665129 is a deficient number, since it is larger than the sum of its proper divisors (1).

6642665129 is an equidigital number, since it uses as much as digits as its factorization.

6642665129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 933120, while the sum is 47.

The square root of 6642665129 is about 81502.5467638895. The cubic root of 6642665129 is about 1879.8107106273.

The spelling of 6642665129 in words is "six billion, six hundred forty-two million, six hundred sixty-five thousand, one hundred twenty-nine".