66706665 has 16 divisors (see below), whose sum is σ = 106893888. Its totient is φ = 35522496.

The previous prime is 66706643. The next prime is 66706667. The reversal of 66706665 is 56660766.

It is not a de Polignac number, because 66706665 - 2¹² = 66702569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66706667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7962 + ... + 14028.

It is an arithmetic number, because the mean of its divisors is an integer number (6680868).

Almost surely, 2^66706665 is an apocalyptic number.

It is an amenable number.

66706665 is a deficient number, since it is larger than the sum of its proper divisors (40187223).

66706665 is a wasteful number, since it uses less digits than its factorization.

66706665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6808.

The product of its (nonzero) digits is 272160, while the sum is 42.

The square root of 66706665 is about 8167.4148296753. The cubic root of 66706665 is about 405.5612094734.

The spelling of 66706665 in words is "sixty-six million, seven hundred six thousand, six hundred sixty-five".