66991167 has 6 divisors (see below), whose sum is σ = 96765032. Its totient is φ = 44660772.

The previous prime is 66991163. The next prime is 66991187. The reversal of 66991167 is 76119966.

It is not a de Polignac number, because 66991167 - 2² = 66991163 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 (66991163) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3721723 + ... + 3721740.

Almost surely, 2^66991167 is an apocalyptic number.

66991167 is a deficient number, since it is larger than the sum of its proper divisors (29773865).

66991167 is a wasteful number, since it uses less digits than its factorization.

66991167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7443469 (or 7443466 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 66991167 is about 8184.8131927369. The cubic root of 66991167 is about 406.1369606759.

The spelling of 66991167 in words is "sixty-six million, nine hundred ninety-one thousand, one hundred sixty-seven".