442323821 has 2 divisors, whose sum is σ = 442323822. Its totient is φ = 442323820.

The previous prime is 442323811. The next prime is 442323851. The reversal of 442323821 is 128323244.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 424566025 + 17757796 = 20605^2 + 4214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-442323821 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 (442323811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 221161910 + 221161911.

It is an arithmetic number, because the mean of its divisors is an integer number (221161911).

Almost surely, 2^442323821 is an apocalyptic number.

It is an amenable number.

442323821 is a deficient number, since it is larger than the sum of its proper divisors (1).

442323821 is an equidigital number, since it uses as much as digits as its factorization.

442323821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9216, while the sum is 29.

The square root of 442323821 is about 21031.4959287256. The cubic root of 442323821 is about 761.9271388691.

The spelling of 442323821 in words is "four hundred forty-two million, three hundred twenty-three thousand, eight hundred twenty-one".