40405555 has 32 divisors (see below), whose sum is σ = 52876800. Its totient is φ = 29568000.

The previous prime is 40405543. The next prime is 40405559. The reversal of 40405555 is 55550404.

40405555 is a nontrivial binomial coefficient, being equal to C(8990, 2).

It is not a de Polignac number, because 40405555 - 2¹⁹ = 39881267 is a prime.

40405555 is a modest number, since divided by 5555 gives 4040 as remainder.

It is not an unprimeable number, because it can be changed into a prime (40405559) 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 31 ways as a sum of consecutive naturals, for example, 400005 + ... + 400105.

It is an arithmetic number, because the mean of its divisors is an integer number (1652400).

Almost surely, 2^40405555 is an apocalyptic number.

40405555 is the 8989-th triangular number and also the 4495-th hexagonal number.

40405555 is the 2997-th centered nonagonal number.

40405555 is a deficient number, since it is larger than the sum of its proper divisors (12471245).

40405555 is a wasteful number, since it uses less digits than its factorization.

40405555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255.

The product of its (nonzero) digits is 10000, while the sum is 28.

The square root of 40405555 is about 6356.5363996441. The cubic root of 40405555 is about 343.1471204592.

Adding to 40405555 its reverse (55550404), we get a palindrome (95955959).

The spelling of 40405555 in words is "forty million, four hundred five thousand, five hundred fifty-five".