66618707 has 4 divisors (see below), whose sum is σ = 66747096. Its totient is φ = 66490320.

The previous prime is 66618683. The next prime is 66618709. The reversal of 66618707 is 70781666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66618707 - 2¹⁴ = 66602323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66618709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63413 + ... + 64454.

It is an arithmetic number, because the mean of its divisors is an integer number (16686774).

Almost surely, 2^66618707 is an apocalyptic number.

66618707 is a deficient number, since it is larger than the sum of its proper divisors (128389).

66618707 is a wasteful number, since it uses less digits than its factorization.

66618707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128388.

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 66618707 is about 8162.0283630970. The cubic root of 66618707 is about 405.3828762524.

The spelling of 66618707 in words is "sixty-six million, six hundred eighteen thousand, seven hundred seven".