3645891 has 40 divisors (see below), whose sum is σ = 6040320. Its totient is φ = 2181168.

The previous prime is 3645877. The next prime is 3645893. The reversal of 3645891 is 1985463.

3645891 is a `hidden beast` number, since 3 + 645 + 8 + 9 + 1 = 666.

It is not a de Polignac number, because 3645891 - 2¹⁵ = 3613123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3645893) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 35346 + ... + 35448.

It is an arithmetic number, because the mean of its divisors is an integer number (151008).

Almost surely, 2^3645891 is an apocalyptic number.

3645891 is a deficient number, since it is larger than the sum of its proper divisors (2394429).

3645891 is a wasteful number, since it uses less digits than its factorization.

3645891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 148 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 3645891 is about 1909.4216401832. The cubic root of 3645891 is about 153.9103740029.

The spelling of 3645891 in words is "three million, six hundred forty-five thousand, eight hundred ninety-one".