42157891 has 2 divisors, whose sum is σ = 42157892. Its totient is φ = 42157890.

The previous prime is 42157879. The next prime is 42157933. The reversal of 42157891 is 19875124.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42157891 - 2⁵ = 42157859 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42157891.

It is not a weakly prime, because it can be changed into another prime (42157811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21078945 + 21078946.

It is an arithmetic number, because the mean of its divisors is an integer number (21078946).

Almost surely, 2^42157891 is an apocalyptic number.

42157891 is a deficient number, since it is larger than the sum of its proper divisors (1).

42157891 is an equidigital number, since it uses as much as digits as its factorization.

42157891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 37.

The square root of 42157891 is about 6492.9108264322. The cubic root of 42157891 is about 348.0377017989.

The spelling of 42157891 in words is "forty-two million, one hundred fifty-seven thousand, eight hundred ninety-one".