3638991 has 12 divisors (see below), whose sum is σ = 5074328. Its totient is φ = 2319504.

The previous prime is 3638959. The next prime is 3638993. The reversal of 3638991 is 1998363.

It is not a de Polignac number, because 3638991 - 2⁵ = 3638959 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 (3638993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 441 + ... + 2733.

Almost surely, 2^3638991 is an apocalyptic number.

3638991 is a deficient number, since it is larger than the sum of its proper divisors (1435337).

3638991 is a wasteful number, since it uses less digits than its factorization.

3638991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2342 (or 2319 counting only the distinct ones).

The product of its digits is 34992, while the sum is 39.

The square root of 3638991 is about 1907.6139546564. The cubic root of 3638991 is about 153.8132187639.

The spelling of 3638991 in words is "three million, six hundred thirty-eight thousand, nine hundred ninety-one".