40021605 has 72 divisors (see below), whose sum is σ = 78551928. Its totient is φ = 18724608.

The previous prime is 40021603. The next prime is 40021607. The reversal of 40021605 is 50612004.

It is a happy number.

40021605 is a `hidden beast` number, since 40 + 0 + 21 + 605 = 666.

40021605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (40021603) and next prime (40021607).

It can be written as a sum of positive squares in 4 ways, for example, as 4809249 + 35212356 = 2193^2 + 5934^2 .

It is not a de Polignac number, because 40021605 - 2¹ = 40021603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40021603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 930714 + ... + 930756.

It is an arithmetic number, because the mean of its divisors is an integer number (1090999).

Almost surely, 2^40021605 is an apocalyptic number.

40021605 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

40021605 is a deficient number, since it is larger than the sum of its proper divisors (38530323).

40021605 is a wasteful number, since it uses less digits than its factorization.

40021605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 40021605 is about 6326.2631149834. The cubic root of 40021605 is about 342.0567516368.

Adding to 40021605 its reverse (50612004), we get a palindrome (90633609).

The spelling of 40021605 in words is "forty million, twenty-one thousand, six hundred five".