42105221 has 2 divisors, whose sum is σ = 42105222. Its totient is φ = 42105220.

The previous prime is 42105211. The next prime is 42105229. The reversal of 42105221 is 12250124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29757025 + 12348196 = 5455^2 + 3514^2 .

It is a cyclic number.

It is not a de Polignac number, because 42105221 - 2¹⁸ = 41843077 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42105221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42105229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21052610 + 21052611.

It is an arithmetic number, because the mean of its divisors is an integer number (21052611).

Almost surely, 2^42105221 is an apocalyptic number.

It is an amenable number.

42105221 is a deficient number, since it is larger than the sum of its proper divisors (1).

42105221 is an equidigital number, since it uses as much as digits as its factorization.

42105221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 42105221 is about 6488.8535967457. The cubic root of 42105221 is about 347.8927009886.

Adding to 42105221 its reverse (12250124), we get a palindrome (54355345).

The spelling of 42105221 in words is "forty-two million, one hundred five thousand, two hundred twenty-one".