4394021 has 2 divisors, whose sum is σ = 4394022. Its totient is φ = 4394020.

The previous prime is 4393999. The next prime is 4394023. The reversal of 4394021 is 1204934.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4368100 + 25921 = 2090^2 + 161^2 .

It is a cyclic number.

It is not a de Polignac number, because 4394021 - 2⁶ = 4393957 is a prime.

Together with 4394023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4394023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2197010 + 2197011.

It is an arithmetic number, because the mean of its divisors is an integer number (2197011).

Almost surely, 2^4394021 is an apocalyptic number.

It is an amenable number.

4394021 is a deficient number, since it is larger than the sum of its proper divisors (1).

4394021 is an equidigital number, since it uses as much as digits as its factorization.

4394021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 4394021 is about 2096.1920236467. The cubic root of 4394021 is about 163.7899974163.

Adding to 4394021 its reverse (1204934), we get a palindrome (5598955).

The spelling of 4394021 in words is "four million, three hundred ninety-four thousand, twenty-one".