66591918 has 24 divisors (see below), whose sum is σ = 145153008. Its totient is φ = 22063392.

The previous prime is 66591883. The next prime is 66591919. The reversal of 66591918 is 81919566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66591919) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8071 + ... + 14082.

It is an arithmetic number, because the mean of its divisors is an integer number (6048042).

Almost surely, 2^66591918 is an apocalyptic number.

66591918 is an abundant number, since it is smaller than the sum of its proper divisors (78561090).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66591918 is a wasteful number, since it uses less digits than its factorization.

66591918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22328 (or 22325 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The square root of 66591918 is about 8160.3871231701. The cubic root of 66591918 is about 405.3285308673.

The spelling of 66591918 in words is "sixty-six million, five hundred ninety-one thousand, nine hundred eighteen".