3939921 has 20 divisors (see below), whose sum is σ = 5947392. Its totient is φ = 2599128.

The previous prime is 3939919. The next prime is 3939931. The reversal of 3939921 is 1299393.

3939921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 3939921 - 2¹ = 3939919 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3939931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10096 + ... + 10478.

Almost surely, 2^3939921 is an apocalyptic number.

It is an amenable number.

3939921 is a deficient number, since it is larger than the sum of its proper divisors (2007471).

3939921 is a wasteful number, since it uses less digits than its factorization.

3939921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522 (or 513 counting only the distinct ones).

The product of its digits is 13122, while the sum is 36.

The square root of 3939921 is about 1984.9234242157. The cubic root of 3939921 is about 157.9413471341.

The spelling of 3939921 in words is "three million, nine hundred thirty-nine thousand, nine hundred twenty-one".