42089681 has 2 divisors, whose sum is σ = 42089682. Its totient is φ = 42089680.

The previous prime is 42089651. The next prime is 42089687. The reversal of 42089681 is 18698024.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37210000 + 4879681 = 6100^2 + 2209^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42089681 is a prime.

It is a super-2 number, since 2×42089681² = 3543082493363522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (42089687) 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, 21044840 + 21044841.

It is an arithmetic number, because the mean of its divisors is an integer number (21044841).

Almost surely, 2^42089681 is an apocalyptic number.

It is an amenable number.

42089681 is a deficient number, since it is larger than the sum of its proper divisors (1).

42089681 is an equidigital number, since it uses as much as digits as its factorization.

42089681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 42089681 is about 6487.6560482196. The cubic root of 42089681 is about 347.8498961797.

The spelling of 42089681 in words is "forty-two million, eighty-nine thousand, six hundred eighty-one".