3964921 has 4 divisors (see below), whose sum is σ = 3969700. Its totient is φ = 3960144.

The previous prime is 3964913. The next prime is 3964937. The reversal of 3964921 is 1294693.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1440000 + 2524921 = 1200^2 + 1589^2 .

It is a cyclic number.

It is not a de Polignac number, because 3964921 - 2³ = 3964913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3964951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 786 + ... + 2923.

It is an arithmetic number, because the mean of its divisors is an integer number (992425).

Almost surely, 2^3964921 is an apocalyptic number.

It is an amenable number.

3964921 is a deficient number, since it is larger than the sum of its proper divisors (4779).

3964921 is a wasteful number, since it uses less digits than its factorization.

3964921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4778.

The product of its digits is 11664, while the sum is 34.

The square root of 3964921 is about 1991.2109380977. The cubic root of 3964921 is about 158.2747050403.

The spelling of 3964921 in words is "three million, nine hundred sixty-four thousand, nine hundred twenty-one".