42166391 has 2 divisors, whose sum is σ = 42166392. Its totient is φ = 42166390.

The previous prime is 42166387. The next prime is 42166393. The reversal of 42166391 is 19366124.

42166391 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 42166391 - 2² = 42166387 is a prime.

Together with 42166393, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42166393) 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, 21083195 + 21083196.

It is an arithmetic number, because the mean of its divisors is an integer number (21083196).

Almost surely, 2^42166391 is an apocalyptic number.

42166391 is a deficient number, since it is larger than the sum of its proper divisors (1).

42166391 is an equidigital number, since it uses as much as digits as its factorization.

42166391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 32.

The square root of 42166391 is about 6493.5653534865. The cubic root of 42166391 is about 348.0610910277.

The spelling of 42166391 in words is "forty-two million, one hundred sixty-six thousand, three hundred ninety-one".