6639539 has 8 divisors (see below), whose sum is σ = 6852768. Its totient is φ = 6428160.

The previous prime is 6639533. The next prime is 6639547. The reversal of 6639539 is 9359366.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6639539 - 2¹⁶ = 6574003 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6639496 and 6639505.

It is not an unprimeable number, because it can be changed into a prime (6639533) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11219 + ... + 11795.

It is an arithmetic number, because the mean of its divisors is an integer number (856596).

Almost surely, 2^6639539 is an apocalyptic number.

6639539 is a deficient number, since it is larger than the sum of its proper divisors (213229).

6639539 is a wasteful number, since it uses less digits than its factorization.

6639539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925.

The product of its digits is 131220, while the sum is 41.

The square root of 6639539 is about 2576.7302924443. The cubic root of 6639539 is about 187.9515776151.

The spelling of 6639539 in words is "six million, six hundred thirty-nine thousand, five hundred thirty-nine".