4381921 has 2 divisors, whose sum is σ = 4381922. Its totient is φ = 4381920.

The previous prime is 4381879. The next prime is 4381931. The reversal of 4381921 is 1291834.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3381921 + 1000000 = 1839^2 + 1000^2 .

It is a cyclic number.

It is not a de Polignac number, because 4381921 - 2⁹ = 4381409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 4381921.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4381931) 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 as a sum of consecutive naturals, namely, 2190960 + 2190961.

It is an arithmetic number, because the mean of its divisors is an integer number (2190961).

Almost surely, 2^4381921 is an apocalyptic number.

It is an amenable number.

4381921 is a deficient number, since it is larger than the sum of its proper divisors (1).

4381921 is an equidigital number, since it uses as much as digits as its factorization.

4381921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 28.

The square root of 4381921 is about 2093.3038479877. The cubic root of 4381921 is about 163.6395140714.

The spelling of 4381921 in words is "four million, three hundred eighty-one thousand, nine hundred twenty-one".