6440979 has 4 divisors (see below), whose sum is σ = 8587976. Its totient is φ = 4293984.

The previous prime is 6440969. The next prime is 6440983. The reversal of 6440979 is 9790446.

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

It is not a de Polignac number, because 6440979 - 2⁵ = 6440947 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6440939) 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, 1073494 + ... + 1073499.

It is an arithmetic number, because the mean of its divisors is an integer number (2146994).

Almost surely, 2^6440979 is an apocalyptic number.

6440979 is a deficient number, since it is larger than the sum of its proper divisors (2146997).

6440979 is a wasteful number, since it uses less digits than its factorization.

6440979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2146996.

The product of its (nonzero) digits is 54432, while the sum is 39.

The square root of 6440979 is about 2537.9083907817. The cubic root of 6440979 is about 186.0589765574.

The spelling of 6440979 in words is "six million, four hundred forty thousand, nine hundred seventy-nine".