42218081 has 2 divisors, whose sum is σ = 42218082. Its totient is φ = 42218080.

The previous prime is 42217991. The next prime is 42218083. The reversal of 42218081 is 18081224.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32035600 + 10182481 = 5660^2 + 3191^2 .

It is a cyclic number.

It is not a de Polignac number, because 42218081 - 2¹⁰ = 42217057 is a prime.

It is a super-2 number, since 2×42218081² = 3564732726645122, which contains 22 as substring.

Together with 42218083, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42218081.

It is not a weakly prime, because it can be changed into another prime (42218083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21109040 + 21109041.

It is an arithmetic number, because the mean of its divisors is an integer number (21109041).

Almost surely, 2^42218081 is an apocalyptic number.

It is an amenable number.

42218081 is a deficient number, since it is larger than the sum of its proper divisors (1).

42218081 is an equidigital number, since it uses as much as digits as its factorization.

42218081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 42218081 is about 6497.5442283989. The cubic root of 42218081 is about 348.2032574212.

The spelling of 42218081 in words is "forty-two million, two hundred eighteen thousand, eighty-one".