666515677 has 2 divisors, whose sum is σ = 666515678. Its totient is φ = 666515676.

The previous prime is 666515627. The next prime is 666515683. The reversal of 666515677 is 776515666.

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., 628705476 + 37810201 = 25074^2 + 6149^2 .

It is a cyclic number.

It is not a de Polignac number, because 666515677 - 2¹¹ = 666513629 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 666515677.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666515627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333257838 + 333257839.

It is an arithmetic number, because the mean of its divisors is an integer number (333257839).

Almost surely, 2^666515677 is an apocalyptic number.

It is an amenable number.

666515677 is a deficient number, since it is larger than the sum of its proper divisors (1).

666515677 is an equidigital number, since it uses as much as digits as its factorization.

666515677 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1587600, while the sum is 49.

The square root of 666515677 is about 25816.9649068205. The cubic root of 666515677 is about 873.5145089451.

The spelling of 666515677 in words is "six hundred sixty-six million, five hundred fifteen thousand, six hundred seventy-seven".