6639658 has 4 divisors (see below), whose sum is σ = 9959490. Its totient is φ = 3319828.

The previous prime is 6639653. The next prime is 6639679. The reversal of 6639658 is 8569366.

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

It can be written as a sum of positive squares in only one way, i.e., 4380649 + 2259009 = 2093^2 + 1503^2 .

It is not an unprimeable number, because it can be changed into a prime (6639653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1659913 + ... + 1659916.

Almost surely, 2^6639658 is an apocalyptic number.

6639658 is a deficient number, since it is larger than the sum of its proper divisors (3319832).

6639658 is a wasteful number, since it uses less digits than its factorization.

6639658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3319831.

The product of its digits is 233280, while the sum is 43.

The square root of 6639658 is about 2576.7533836206. The cubic root of 6639658 is about 187.9527004895.

The spelling of 6639658 in words is "six million, six hundred thirty-nine thousand, six hundred fifty-eight".