66666515 has 8 divisors (see below), whose sum is σ = 81127008. Its totient is φ = 52581760.

The previous prime is 66666493. The next prime is 66666517. The reversal of 66666515 is 51566666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66666515 - 2²⁰ = 65617939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66666517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 93542 + ... + 94251.

It is an arithmetic number, because the mean of its divisors is an integer number (10140876).

Almost surely, 2^66666515 is an apocalyptic number.

66666515 is a deficient number, since it is larger than the sum of its proper divisors (14460493).

66666515 is a wasteful number, since it uses less digits than its factorization.

66666515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187869.

The product of its digits is 194400, while the sum is 41.

The square root of 66666515 is about 8164.9565216234. The cubic root of 66666515 is about 405.4798255489.

The spelling of 66666515 in words is "sixty-six million, six hundred sixty-six thousand, five hundred fifteen".