3981421 has 2 divisors, whose sum is σ = 3981422. Its totient is φ = 3981420.

The previous prime is 3981407. The next prime is 3981449. The reversal of 3981421 is 1241893.

It is a happy number.

3981421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (3981449) can be obtained adding 3981421 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2368521 + 1612900 = 1539^2 + 1270^2 .

It is an emirp because it is prime and its reverse (1241893) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3981421 - 2⁵ = 3981389 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3981421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3981401) 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, 1990710 + 1990711.

It is an arithmetic number, because the mean of its divisors is an integer number (1990711).

Almost surely, 2^3981421 is an apocalyptic number.

It is an amenable number.

3981421 is a deficient number, since it is larger than the sum of its proper divisors (1).

3981421 is an equidigital number, since it uses as much as digits as its factorization.

3981421 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 3981421 is about 1995.3498440123. The cubic root of 3981421 is about 158.4939543316.

The spelling of 3981421 in words is "three million, nine hundred eighty-one thousand, four hundred twenty-one".