40185581 has 2 divisors, whose sum is σ = 40185582. Its totient is φ = 40185580.

The previous prime is 40185559. The next prime is 40185601. The reversal of 40185581 is 18558104.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37515625 + 2669956 = 6125^2 + 1634^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40185581 is a prime.

It is a super-2 number, since 2×40185581² = 3229761840615122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40185511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20092790 + 20092791.

It is an arithmetic number, because the mean of its divisors is an integer number (20092791).

Almost surely, 2^40185581 is an apocalyptic number.

It is an amenable number.

40185581 is a deficient number, since it is larger than the sum of its proper divisors (1).

40185581 is an equidigital number, since it uses as much as digits as its factorization.

40185581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6400, while the sum is 32.

The square root of 40185581 is about 6339.2098088011. The cubic root of 40185581 is about 342.5232719016.

The spelling of 40185581 in words is "forty million, one hundred eighty-five thousand, five hundred eighty-one".