3656639 has 8 divisors (see below), whose sum is σ = 4323360. Its totient is φ = 3026016.

The previous prime is 3656633. The next prime is 3656641. The reversal of 3656639 is 9366563.

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

It is not a de Polignac number, because 3656639 - 2⁸ = 3656383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3656633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8804 + ... + 9209.

It is an arithmetic number, because the mean of its divisors is an integer number (540420).

Almost surely, 2^3656639 is an apocalyptic number.

3656639 is a deficient number, since it is larger than the sum of its proper divisors (666721).

3656639 is a wasteful number, since it uses less digits than its factorization.

3656639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18049.

The product of its digits is 87480, while the sum is 38.

The square root of 3656639 is about 1912.2340337940. The cubic root of 3656639 is about 154.0614670018.

The spelling of 3656639 in words is "three million, six hundred fifty-six thousand, six hundred thirty-nine".