42121819 has 2 divisors, whose sum is σ = 42121820. Its totient is φ = 42121818.

The previous prime is 42121787. The next prime is 42121843. The reversal of 42121819 is 91812124.

42121819 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 42121819 - 2⁵ = 42121787 is a prime.

It is a super-3 number, since 3×42121819³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is equal to p_2554534 and since 42121819 and 2554534 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (42121889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21060909 + 21060910.

It is an arithmetic number, because the mean of its divisors is an integer number (21060910).

Almost surely, 2^42121819 is an apocalyptic number.

42121819 is a deficient number, since it is larger than the sum of its proper divisors (1).

42121819 is an equidigital number, since it uses as much as digits as its factorization.

42121819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 28.

The square root of 42121819 is about 6490.1324331634. The cubic root of 42121819 is about 347.9384084197.

The spelling of 42121819 in words is "forty-two million, one hundred twenty-one thousand, eight hundred nineteen".