66610191 has 8 divisors (see below), whose sum is σ = 89729584. Its totient is φ = 43948800.

The previous prime is 66610189. The next prime is 66610213. The reversal of 66610191 is 19101666.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66610191 - 2¹ = 66610189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66610111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114160 + ... + 114741.

It is an arithmetic number, because the mean of its divisors is an integer number (11216198).

Almost surely, 2^66610191 is an apocalyptic number.

66610191 is a deficient number, since it is larger than the sum of its proper divisors (23119393).

66610191 is a wasteful number, since it uses less digits than its factorization.

66610191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229001.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 66610191 is about 8161.5066623755. The cubic root of 66610191 is about 405.3656018869.

The spelling of 66610191 in words is "sixty-six million, six hundred ten thousand, one hundred ninety-one".