21042442349 has 2 divisors, whose sum is σ = 21042442350. Its totient is φ = 21042442348.

The previous prime is 21042442307. The next prime is 21042442363. The reversal of 21042442349 is 94324424012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20910606025 + 131836324 = 144605^2 + 11482^2 .

It is a cyclic number.

It is not a de Polignac number, because 21042442349 - 2¹² = 21042438253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21042442649) 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, 10521221174 + 10521221175.

It is an arithmetic number, because the mean of its divisors is an integer number (10521221175).

Almost surely, 2^21042442349 is an apocalyptic number.

It is an amenable number.

21042442349 is a deficient number, since it is larger than the sum of its proper divisors (1).

21042442349 is an equidigital number, since it uses as much as digits as its factorization.

21042442349 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55296, while the sum is 35.

The spelling of 21042442349 in words is "twenty-one billion, forty-two million, four hundred forty-two thousand, three hundred forty-nine".