666161243 has 4 divisors (see below), whose sum is σ = 726721368. Its totient is φ = 605601120.

The previous prime is 666161191. The next prime is 666161273. The reversal of 666161243 is 342161666.

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 666161243 - 2⁶ = 666161179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666161273) 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, 30280046 + ... + 30280067.

It is an arithmetic number, because the mean of its divisors is an integer number (181680342).

Almost surely, 2^666161243 is an apocalyptic number.

666161243 is a deficient number, since it is larger than the sum of its proper divisors (60560125).

666161243 is a wasteful number, since it uses less digits than its factorization.

666161243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60560124.

The product of its digits is 31104, while the sum is 35.

The square root of 666161243 is about 25810.0996317333. The cubic root of 666161243 is about 873.3596448023.

The spelling of 666161243 in words is "six hundred sixty-six million, one hundred sixty-one thousand, two hundred forty-three".