3656891 has 4 divisors (see below), whose sum is σ = 4179312. Its totient is φ = 3134472.

The previous prime is 3656881. The next prime is 3656903. The reversal of 3656891 is 1986563.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1986563 = 241 ⋅8243.

It is a cyclic number.

It is not a de Polignac number, because 3656891 - 2⁶ = 3656827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3656801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 261200 + ... + 261213.

It is an arithmetic number, because the mean of its divisors is an integer number (1044828).

Almost surely, 2^3656891 is an apocalyptic number.

3656891 is a deficient number, since it is larger than the sum of its proper divisors (522421).

3656891 is an equidigital number, since it uses as much as digits as its factorization.

3656891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522420.

The product of its digits is 38880, while the sum is 38.

The square root of 3656891 is about 1912.2999241751. The cubic root of 3656891 is about 154.0650060074.

The spelling of 3656891 in words is "three million, six hundred fifty-six thousand, eight hundred ninety-one".