666566601 has 16 divisors (see below), whose sum is σ = 905472000. Its totient is φ = 436047248.

The previous prime is 666566599. The next prime is 666566603. The reversal of 666566601 is 106665666.

It is an interprime number because it is at equal distance from previous prime (666566599) and next prime (666566603).

It is a cyclic number.

It is not a de Polignac number, because 666566601 - 2¹ = 666566599 is a prime.

It is a super-2 number, since 2×666566601² = 888622067137386402, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (666566603) 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, 102880 + ... + 109166.

It is an arithmetic number, because the mean of its divisors is an integer number (56592000).

Almost surely, 2^666566601 is an apocalyptic number.

It is an amenable number.

666566601 is a deficient number, since it is larger than the sum of its proper divisors (238905399).

666566601 is a wasteful number, since it uses less digits than its factorization.

666566601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6948.

The product of its (nonzero) digits is 233280, while the sum is 42.

The square root of 666566601 is about 25817.9511386942. The cubic root of 666566601 is about 873.5367548435.

The spelling of 666566601 in words is "six hundred sixty-six million, five hundred sixty-six thousand, six hundred one".