402243221 has 2 divisors, whose sum is σ = 402243222. Its totient is φ = 402243220.

The previous prime is 402243181. The next prime is 402243223. The reversal of 402243221 is 122342204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351975121 + 50268100 = 18761^2 + 7090^2 .

It is a cyclic number.

It is not a de Polignac number, because 402243221 - 2⁶ = 402243157 is a prime.

It is a Sophie Germain prime.

Together with 402243223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 402243193 and 402243202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402243223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201121610 + 201121611.

It is an arithmetic number, because the mean of its divisors is an integer number (201121611).

Almost surely, 2^402243221 is an apocalyptic number.

It is an amenable number.

402243221 is a deficient number, since it is larger than the sum of its proper divisors (1).

402243221 is an equidigital number, since it uses as much as digits as its factorization.

402243221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 402243221 is about 20056.0021190665. The cubic root of 402243221 is about 738.1810824411.

Adding to 402243221 its reverse (122342204), we get a palindrome (524585425).

The spelling of 402243221 in words is "four hundred two million, two hundred forty-three thousand, two hundred twenty-one".