3945891 has 4 divisors (see below), whose sum is σ = 5261192. Its totient is φ = 2630592.

The previous prime is 3945883. The next prime is 3945913. The reversal of 3945891 is 1985493.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 3945891 - 2³ = 3945883 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3945841) 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, 657646 + ... + 657651.

It is an arithmetic number, because the mean of its divisors is an integer number (1315298).

Almost surely, 2^3945891 is an apocalyptic number.

3945891 is a deficient number, since it is larger than the sum of its proper divisors (1315301).

3945891 is a wasteful number, since it uses less digits than its factorization.

3945891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1315300.

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

The square root of 3945891 is about 1986.4266913229. The cubic root of 3945891 is about 158.0210808810.

The spelling of 3945891 in words is "three million, nine hundred forty-five thousand, eight hundred ninety-one".