40668181 has 4 divisors (see below), whose sum is σ = 40927372. Its totient is φ = 40408992.

The previous prime is 40668167. The next prime is 40668191. The reversal of 40668181 is 18186604.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12895281 + 27772900 = 3591^2 + 5270^2 .

It is a cyclic number.

It is not a de Polignac number, because 40668181 - 2¹¹ = 40666133 is a prime.

It is a super-2 number, since 2×40668181² = 3307801891697522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40668101) 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 3 ways as a sum of consecutive naturals, for example, 129360 + ... + 129673.

It is an arithmetic number, because the mean of its divisors is an integer number (10231843).

Almost surely, 2^40668181 is an apocalyptic number.

It is an amenable number.

40668181 is a deficient number, since it is larger than the sum of its proper divisors (259191).

40668181 is a wasteful number, since it uses less digits than its factorization.

40668181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259190.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 40668181 is about 6377.1608886714. The cubic root of 40668181 is about 343.8889723041. Note that the first 3 decimals are identical.

The spelling of 40668181 in words is "forty million, six hundred sixty-eight thousand, one hundred eighty-one".