40436581 has 2 divisors, whose sum is σ = 40436582. Its totient is φ = 40436580.

The previous prime is 40436573. The next prime is 40436593. The reversal of 40436581 is 18563404.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27720225 + 12716356 = 5265^2 + 3566^2 .

It is a cyclic number.

It is not a de Polignac number, because 40436581 - 2³ = 40436573 is a prime.

It is a super-2 number, since 2×40436581² = 3270234165939122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40436281) 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, 20218290 + 20218291.

It is an arithmetic number, because the mean of its divisors is an integer number (20218291).

Almost surely, 2^40436581 is an apocalyptic number.

It is an amenable number.

40436581 is a deficient number, since it is larger than the sum of its proper divisors (1).

40436581 is an equidigital number, since it uses as much as digits as its factorization.

40436581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 40436581 is about 6358.9764113417. The cubic root of 40436581 is about 343.2349281769.

Adding to 40436581 its reverse (18563404), we get a palindrome (58999985).

The spelling of 40436581 in words is "forty million, four hundred thirty-six thousand, five hundred eighty-one".