666376517 has 4 divisors (see below), whose sum is σ = 673246476. Its totient is φ = 659506560.

The previous prime is 666376511. The next prime is 666376519. The reversal of 666376517 is 715673666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 116661601 + 549714916 = 10801^2 + 23446^2 .

It is a cyclic number.

It is not a de Polignac number, because 666376517 - 2⁶ = 666376453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666376511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3434834 + ... + 3435027.

It is an arithmetic number, because the mean of its divisors is an integer number (168311619).

Almost surely, 2^666376517 is an apocalyptic number.

It is an amenable number.

666376517 is a deficient number, since it is larger than the sum of its proper divisors (6869959).

666376517 is an equidigital number, since it uses as much as digits as its factorization.

666376517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6869958.

The product of its digits is 952560, while the sum is 47.

The square root of 666376517 is about 25814.2696390969. The cubic root of 666376517 is about 873.4537118055.

The spelling of 666376517 in words is "six hundred sixty-six million, three hundred seventy-six thousand, five hundred seventeen".