3813921 has 6 divisors (see below), whose sum is σ = 5509010. Its totient is φ = 2542608.

The previous prime is 3813913. The next prime is 3813941. The reversal of 3813921 is 1293183.

It can be written as a sum of positive squares in only one way, i.e., 3744225 + 69696 = 1935^2 + 264^2 .

It is not a de Polignac number, because 3813921 - 2³ = 3813913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3813941) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 211876 + ... + 211893.

Almost surely, 2^3813921 is an apocalyptic number.

It is an amenable number.

3813921 is a deficient number, since it is larger than the sum of its proper divisors (1695089).

3813921 is a wasteful number, since it uses less digits than its factorization.

3813921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423775 (or 423772 counting only the distinct ones).

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

The square root of 3813921 is about 1952.9262658892. The cubic root of 3813921 is about 156.2394006677.

The spelling of 3813921 in words is "three million, eight hundred thirteen thousand, nine hundred twenty-one".