40166561 has 4 divisors (see below), whose sum is σ = 40197312. Its totient is φ = 40135812.

The previous prime is 40166557. The next prime is 40166569. The reversal of 40166561 is 16566104.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 40166561 - 2² = 40166557 is a prime.

It is a super-2 number, since 2×40166561² = 3226705245133442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40166569) 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, 13325 + ... + 16058.

It is an arithmetic number, because the mean of its divisors is an integer number (10049328).

Almost surely, 2^40166561 is an apocalyptic number.

It is an amenable number.

40166561 is a deficient number, since it is larger than the sum of its proper divisors (30751).

40166561 is a wasteful number, since it uses less digits than its factorization.

40166561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30750.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 40166561 is about 6337.7094442709. The cubic root of 40166561 is about 342.4692241514.

The spelling of 40166561 in words is "forty million, one hundred sixty-six thousand, five hundred sixty-one".