3891321 has 20 divisors (see below), whose sum is σ = 6644352. Its totient is φ = 2223288.

The previous prime is 3891287. The next prime is 3891323. The reversal of 3891321 is 1231983.

It is not a de Polignac number, because 3891321 - 2¹⁷ = 3760249 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (3891323) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2865 + ... + 3998.

Almost surely, 2^3891321 is an apocalyptic number.

It is an amenable number.

3891321 is a deficient number, since it is larger than the sum of its proper divisors (2753031).

3891321 is an equidigital number, since it uses as much as digits as its factorization.

3891321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6882 (or 6873 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 3891321 is about 1972.6431506991. The cubic root of 3891321 is about 157.2892419101.

The spelling of 3891321 in words is "three million, eight hundred ninety-one thousand, three hundred twenty-one".