3811921 has 2 divisors, whose sum is σ = 3811922. Its totient is φ = 3811920.

The previous prime is 3811909. The next prime is 3811939. The reversal of 3811921 is 1291183.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3651921 + 160000 = 1911^2 + 400^2 .

It is a cyclic number.

It is not a de Polignac number, because 3811921 - 2⁵ = 3811889 is a prime.

It is not a weakly prime, because it can be changed into another prime (3811121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1905960 + 1905961.

It is an arithmetic number, because the mean of its divisors is an integer number (1905961).

Almost surely, 2^3811921 is an apocalyptic number.

It is an amenable number.

3811921 is a deficient number, since it is larger than the sum of its proper divisors (1).

3811921 is an equidigital number, since it uses as much as digits as its factorization.

3811921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 25.

The square root of 3811921 is about 1952.4141466400. The cubic root of 3811921 is about 156.2120855207.

The spelling of 3811921 in words is "three million, eight hundred eleven thousand, nine hundred twenty-one".