3891945 has 32 divisors (see below), whose sum is σ = 6739200. Its totient is φ = 1912064.

The previous prime is 3891917. The next prime is 3891971. The reversal of 3891945 is 5491983.

3891945 = 230² + 231² + ... + 287².

It is a cyclic number.

It is not a de Polignac number, because 3891945 - 2⁵ = 3891913 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9811 + ... + 10199.

It is an arithmetic number, because the mean of its divisors is an integer number (210600).

Almost surely, 2^3891945 is an apocalyptic number.

It is an amenable number.

3891945 is a deficient number, since it is larger than the sum of its proper divisors (2847255).

3891945 is a wasteful number, since it uses less digits than its factorization.

3891945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 449.

The product of its digits is 38880, while the sum is 39.

The square root of 3891945 is about 1972.8013077855. The cubic root of 3891945 is about 157.2976489302.

The spelling of 3891945 in words is "three million, eight hundred ninety-one thousand, nine hundred forty-five".