66618923 has 4 divisors (see below), whose sum is σ = 76135920. Its totient is φ = 57101928.

The previous prime is 66618917. The next prime is 66618931. The reversal of 66618923 is 32981666.

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 66618923 - 2¹⁶ = 66553387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66618913) 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, 4758488 + ... + 4758501.

It is an arithmetic number, because the mean of its divisors is an integer number (19033980).

Almost surely, 2^66618923 is an apocalyptic number.

66618923 is a deficient number, since it is larger than the sum of its proper divisors (9516997).

66618923 is an equidigital number, since it uses as much as digits as its factorization.

66618923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9516996.

The product of its digits is 93312, while the sum is 41.

The square root of 66618923 is about 8162.0415950913. The cubic root of 66618923 is about 405.3833143806.

The spelling of 66618923 in words is "sixty-six million, six hundred eighteen thousand, nine hundred twenty-three".