3999421 has 2 divisors, whose sum is σ = 3999422. Its totient is φ = 3999420.

The previous prime is 3999389. The next prime is 3999439. The reversal of 3999421 is 1249993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3944196 + 55225 = 1986^2 + 235^2 .

It is a cyclic number.

It is not a de Polignac number, because 3999421 - 2⁵ = 3999389 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3999461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1999710 + 1999711.

It is an arithmetic number, because the mean of its divisors is an integer number (1999711).

Almost surely, 2^3999421 is an apocalyptic number.

It is an amenable number.

3999421 is a deficient number, since it is larger than the sum of its proper divisors (1).

3999421 is an equidigital number, since it uses as much as digits as its factorization.

3999421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 37.

The square root of 3999421 is about 1999.8552447615. The cubic root of 3999421 is about 158.7324456172.

The spelling of 3999421 in words is "three million, nine hundred ninety-nine thousand, four hundred twenty-one".