40405581 has 16 divisors (see below), whose sum is σ = 60233920. Its totient is φ = 26768880.

The previous prime is 40405559. The next prime is 40405601. The reversal of 40405581 is 18550404.

40405581 is a `hidden beast` number, since 40 + 40 + 5 + 581 = 666.

It is not a de Polignac number, because 40405581 - 2⁹ = 40405069 is a prime.

It is a super-2 number, since 2×40405581² = 3265221951895122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40403581) 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 in 15 ways as a sum of consecutive naturals, for example, 190 + ... + 8991.

It is an arithmetic number, because the mean of its divisors is an integer number (3764620).

Almost surely, 2^40405581 is an apocalyptic number.

It is an amenable number.

40405581 is a deficient number, since it is larger than the sum of its proper divisors (19828339).

40405581 is a wasteful number, since it uses less digits than its factorization.

40405581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9353 (or 9347 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 40405581 is about 6356.5384447827. The cubic root of 40405581 is about 343.1471940614.

Adding to 40405581 its reverse (18550404), we get a palindrome (58955985).

The spelling of 40405581 in words is "forty million, four hundred five thousand, five hundred eighty-one".