3891645 has 24 divisors (see below), whose sum is σ = 6997536. Its totient is φ = 2074896.

The previous prime is 3891593. The next prime is 3891659. The reversal of 3891645 is 5461983.

3891645 is a `hidden beast` number, since 3 + 8 + 9 + 1 + 645 = 666.

It is not a de Polignac number, because 3891645 - 2⁸ = 3891389 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 387 + ... + 2816.

It is an arithmetic number, because the mean of its divisors is an integer number (291564).

Almost surely, 2^3891645 is an apocalyptic number.

It is an amenable number.

3891645 is a deficient number, since it is larger than the sum of its proper divisors (3105891).

3891645 is an equidigital number, since it uses as much as digits as its factorization.

3891645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3223 (or 3211 counting only the distinct ones).

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

The square root of 3891645 is about 1972.7252723073. The cubic root of 3891645 is about 157.2936072058.

The spelling of 3891645 in words is "three million, eight hundred ninety-one thousand, six hundred forty-five".