42090091 has 2 divisors, whose sum is σ = 42090092. Its totient is φ = 42090090.

The previous prime is 42090071. The next prime is 42090101. The reversal of 42090091 is 19009024.

42090091 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 42090091 - 2⁷ = 42089963 is a prime.

It is not a weakly prime, because it can be changed into another prime (42090031) 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, 21045045 + 21045046.

It is an arithmetic number, because the mean of its divisors is an integer number (21045046).

Almost surely, 2^42090091 is an apocalyptic number.

42090091 is a deficient number, since it is larger than the sum of its proper divisors (1).

42090091 is an equidigital number, since it uses as much as digits as its factorization.

42090091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 42090091 is about 6487.6876466118. The cubic root of 42090091 is about 347.8510256569.

The spelling of 42090091 in words is "forty-two million, ninety thousand, ninety-one".