42641821 has 2 divisors, whose sum is σ = 42641822. Its totient is φ = 42641820.

The previous prime is 42641813. The next prime is 42641843. The reversal of 42641821 is 12814624.

42641821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40819321 + 1822500 = 6389^2 + 1350^2 .

It is a cyclic number.

It is not a de Polignac number, because 42641821 - 2³ = 42641813 is a prime.

It is equal to p_2584225 and since 42641821 and 2584225 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42641821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42641801) 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, 21320910 + 21320911.

It is an arithmetic number, because the mean of its divisors is an integer number (21320911).

Almost surely, 2^42641821 is an apocalyptic number.

It is an amenable number.

42641821 is a deficient number, since it is larger than the sum of its proper divisors (1).

42641821 is an equidigital number, since it uses as much as digits as its factorization.

42641821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3072, while the sum is 28.

The square root of 42641821 is about 6530.0705202930. The cubic root of 42641821 is about 349.3643455713.

The spelling of 42641821 in words is "forty-two million, six hundred forty-one thousand, eight hundred twenty-one".