6639974 has 16 divisors (see below), whose sum is σ = 11119680. Its totient is φ = 2947560.

The previous prime is 6639943. The next prime is 6639989. The reversal of 6639974 is 4799366.

It is a d-powerful number, because it can be written as 6⁶ + 6⁷ + 3³ + 9³ + 9⁶ + 7⁸ + 4⁷ .

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2564 + ... + 4455.

It is an arithmetic number, because the mean of its divisors is an integer number (694980).

Almost surely, 2^6639974 is an apocalyptic number.

6639974 is a deficient number, since it is larger than the sum of its proper divisors (4479706).

6639974 is a wasteful number, since it uses less digits than its factorization.

6639974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7075.

The product of its digits is 244944, while the sum is 44.

The square root of 6639974 is about 2576.8147003617. The cubic root of 6639974 is about 187.9556821747.

The spelling of 6639974 in words is "six million, six hundred thirty-nine thousand, nine hundred seventy-four".