442155221 has 2 divisors, whose sum is σ = 442155222. Its totient is φ = 442155220.

The previous prime is 442155173. The next prime is 442155223. The reversal of 442155221 is 122551244.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 342435025 + 99720196 = 18505^2 + 9986^2 .

It is a cyclic number.

It is not a de Polignac number, because 442155221 - 2¹⁸ = 441893077 is a prime.

It is a Sophie Germain prime.

Together with 442155223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (442155223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 221077610 + 221077611.

It is an arithmetic number, because the mean of its divisors is an integer number (221077611).

Almost surely, 2^442155221 is an apocalyptic number.

It is an amenable number.

442155221 is a deficient number, since it is larger than the sum of its proper divisors (1).

442155221 is an equidigital number, since it uses as much as digits as its factorization.

442155221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3200, while the sum is 26.

The square root of 442155221 is about 21027.4872726153. The cubic root of 442155221 is about 761.8303189718.

The spelling of 442155221 in words is "four hundred forty-two million, one hundred fifty-five thousand, two hundred twenty-one".