3951921 has 4 divisors (see below), whose sum is σ = 5269232. Its totient is φ = 2634612.

The previous prime is 3951907. The next prime is 3951923. The reversal of 3951921 is 1291593.

3951921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 3951921 - 2⁷ = 3951793 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 (3951923) 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 3 ways as a sum of consecutive naturals, for example, 658651 + ... + 658656.

It is an arithmetic number, because the mean of its divisors is an integer number (1317308).

Almost surely, 2^3951921 is an apocalyptic number.

It is an amenable number.

3951921 is a deficient number, since it is larger than the sum of its proper divisors (1317311).

3951921 is a wasteful number, since it uses less digits than its factorization.

3951921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1317310.

The product of its digits is 2430, while the sum is 30.

The square root of 3951921 is about 1987.9439126897. The cubic root of 3951921 is about 158.1015343745.

The spelling of 3951921 in words is "three million, nine hundred fifty-one thousand, nine hundred twenty-one".