6639902 has 4 divisors (see below), whose sum is σ = 9959856. Its totient is φ = 3319950.

The previous prime is 6639889. The next prime is 6639907. The reversal of 6639902 is 2099366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2099366 = 2 ⋅1049683.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6639907) by changing a digit.

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 as a sum of consecutive naturals, namely, 1659974 + ... + 1659977.

It is an arithmetic number, because the mean of its divisors is an integer number (2489964).

Almost surely, 2^6639902 is an apocalyptic number.

6639902 is a deficient number, since it is larger than the sum of its proper divisors (3319954).

6639902 is a wasteful number, since it uses less digits than its factorization.

6639902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3319953.

The product of its (nonzero) digits is 17496, while the sum is 35.

The square root of 6639902 is about 2576.8007295870. The cubic root of 6639902 is about 187.9550028117.

The spelling of 6639902 in words is "six million, six hundred thirty-nine thousand, nine hundred two".