666500015 has 4 divisors (see below), whose sum is σ = 799800024. Its totient is φ = 533200008.

The previous prime is 666499913. The next prime is 666500033. The reversal of 666500015 is 510005666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 510005666 = 2 ⋅255002833.

It is a cyclic number.

It is not a de Polignac number, because 666500015 - 2²⁰ = 665451439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66649997 + ... + 66650006.

It is an arithmetic number, because the mean of its divisors is an integer number (199950006).

Almost surely, 2^666500015 is an apocalyptic number.

666500015 is a deficient number, since it is larger than the sum of its proper divisors (133300009).

666500015 is a wasteful number, since it uses less digits than its factorization.

666500015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133300008.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 666500015 is about 25816.6615773612. The cubic root of 666500015 is about 873.5076668498.

The spelling of 666500015 in words is "six hundred sixty-six million, five hundred thousand, fifteen".