66040665 has 16 divisors (see below), whose sum is σ = 111881088. Its totient is φ = 33149696.

The previous prime is 66040657. The next prime is 66040669. The reversal of 66040665 is 56604066.

It is a cyclic number.

It is not a de Polignac number, because 66040665 - 2³ = 66040657 is a prime.

It is a super-2 number, since 2×66040665² = 8722738867284450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66040669) 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, 129237 + ... + 129746.

It is an arithmetic number, because the mean of its divisors is an integer number (6992568).

Almost surely, 2^66040665 is an apocalyptic number.

It is an amenable number.

66040665 is a deficient number, since it is larger than the sum of its proper divisors (45840423).

66040665 is a wasteful number, since it uses less digits than its factorization.

66040665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259008.

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 66040665 is about 8126.5407769850. The cubic root of 66040665 is about 404.2069835196.

The spelling of 66040665 in words is "sixty-six million, forty thousand, six hundred sixty-five".