66947091 has 4 divisors (see below), whose sum is σ = 89262792. Its totient is φ = 44631392.

The previous prime is 66947081. The next prime is 66947093. The reversal of 66947091 is 19074966.

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 66947091 - 2²² = 62752787 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66947093) 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, 11157846 + ... + 11157851.

It is an arithmetic number, because the mean of its divisors is an integer number (22315698).

Almost surely, 2^66947091 is an apocalyptic number.

66947091 is a deficient number, since it is larger than the sum of its proper divisors (22315701).

66947091 is a wasteful number, since it uses less digits than its factorization.

66947091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22315700.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 66947091 is about 8182.1202020014. The cubic root of 66947091 is about 406.0478702241.

The spelling of 66947091 in words is "sixty-six million, nine hundred forty-seven thousand, ninety-one".