42093781 has 2 divisors, whose sum is σ = 42093782. Its totient is φ = 42093780.

The previous prime is 42093739. The next prime is 42093809. The reversal of 42093781 is 18739024.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28836900 + 13256881 = 5370^2 + 3641^2 .

It is a cyclic number.

It is not a de Polignac number, because 42093781 - 2²¹ = 39996629 is a prime.

It is a super-2 number, since 2×42093781² = 3543772797751922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42093281) 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, 21046890 + 21046891.

It is an arithmetic number, because the mean of its divisors is an integer number (21046891).

Almost surely, 2^42093781 is an apocalyptic number.

It is an amenable number.

42093781 is a deficient number, since it is larger than the sum of its proper divisors (1).

42093781 is an equidigital number, since it uses as much as digits as its factorization.

42093781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 42093781 is about 6487.9720252171. The cubic root of 42093781 is about 347.8611906208.

The spelling of 42093781 in words is "forty-two million, ninety-three thousand, seven hundred eighty-one".