6666291997 has 4 divisors (see below), whose sum is σ = 6750675520. Its totient is φ = 6581908476.

The previous prime is 6666291977. The next prime is 6666292013. The reversal of 6666291997 is 7991926666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6666291997 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 (6666291937) 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, 42191643 + ... + 42191800.

It is an arithmetic number, because the mean of its divisors is an integer number (1687668880).

Almost surely, 2^6666291997 is an apocalyptic number.

It is an amenable number.

6666291997 is a deficient number, since it is larger than the sum of its proper divisors (84383523).

6666291997 is an equidigital number, since it uses as much as digits as its factorization.

6666291997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84383522.

The product of its digits is 13226976, while the sum is 61.

The square root of 6666291997 is about 81647.3636867719. The cubic root of 6666291997 is about 1882.0367993360.

The spelling of 6666291997 in words is "six billion, six hundred sixty-six million, two hundred ninety-one thousand, nine hundred ninety-seven".