66242191 has 4 divisors (see below), whose sum is σ = 67365000. Its totient is φ = 65119384.

The previous prime is 66242179. The next prime is 66242201. The reversal of 66242191 is 19124266.

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 66242191 - 2⁵ = 66242159 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 (66242161) 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, 561316 + ... + 561433.

It is an arithmetic number, because the mean of its divisors is an integer number (16841250).

Almost surely, 2^66242191 is an apocalyptic number.

66242191 is a deficient number, since it is larger than the sum of its proper divisors (1122809).

66242191 is a wasteful number, since it uses less digits than its factorization.

66242191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1122808.

The product of its digits is 5184, while the sum is 31.

The square root of 66242191 is about 8138.9305808564. The cubic root of 66242191 is about 404.6177178198.

The spelling of 66242191 in words is "sixty-six million, two hundred forty-two thousand, one hundred ninety-one".