40166781 has 4 divisors (see below), whose sum is σ = 53555712. Its totient is φ = 26777852.

The previous prime is 40166761. The next prime is 40166803. The reversal of 40166781 is 18766104.

It is a happy number.

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 40166781 - 2¹³ = 40158589 is a prime.

It is a super-2 number, since 2×40166781² = 3226740591803922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40166761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6694461 + ... + 6694466.

It is an arithmetic number, because the mean of its divisors is an integer number (13388928).

Almost surely, 2^40166781 is an apocalyptic number.

It is an amenable number.

40166781 is a deficient number, since it is larger than the sum of its proper divisors (13388931).

40166781 is a wasteful number, since it uses less digits than its factorization.

40166781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13388930.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 40166781 is about 6337.7268006755. The cubic root of 40166781 is about 342.4698494069.

The spelling of 40166781 in words is "forty million, one hundred sixty-six thousand, seven hundred eighty-one".