66650001 has 16 divisors (see below), whose sum is σ = 97910208. Its totient is φ = 39992000.

The previous prime is 66649993. The next prime is 66650027. The reversal of 66650001 is 10005666.

It is a cyclic number.

It is not a de Polignac number, because 66650001 - 2³ = 66649993 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66650401) 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, 6666 + ... + 13331.

It is an arithmetic number, because the mean of its divisors is an integer number (6119388).

Almost surely, 2^66650001 is an apocalyptic number.

66650001 is the 6666-th pentagonal number.

It is an amenable number.

66650001 is a deficient number, since it is larger than the sum of its proper divisors (31260207).

66650001 is a wasteful number, since it uses less digits than its factorization.

66650001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20112.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 66650001 is about 8163.9451859992. The cubic root of 66650001 is about 405.4463422387.

Adding to 66650001 its reverse (10005666), we get a palindrome (76655667).

The spelling of 66650001 in words is "sixty-six million, six hundred fifty thousand, one".