6661979 has 4 divisors (see below), whose sum is σ = 6674376. Its totient is φ = 6649584.

The previous prime is 6661957. The next prime is 6661987. The reversal of 6661979 is 9791666.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6661979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6661079) 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, 5354 + ... + 6479.

It is an arithmetic number, because the mean of its divisors is an integer number (1668594).

Almost surely, 2^6661979 is an apocalyptic number.

6661979 is a deficient number, since it is larger than the sum of its proper divisors (12397).

6661979 is a wasteful number, since it uses less digits than its factorization.

6661979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12396.

The product of its digits is 122472, while the sum is 44.

The square root of 6661979 is about 2581.0809750955. The cubic root of 6661979 is about 188.1630828007.

The spelling of 6661979 in words is "six million, six hundred sixty-one thousand, nine hundred seventy-nine".