40165639891 has 4 divisors (see below), whose sum is σ = 43255304512. Its totient is φ = 37075975272.

The previous prime is 40165639853. The next prime is 40165639963. The reversal of 40165639891 is 19893656104.

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

It is a cyclic number.

It is not a de Polignac number, because 40165639891 - 2⁷ = 40165639763 is a prime.

It is a super-2 number, since 2×40165639891² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40165630891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1544832291 + ... + 1544832316.

It is an arithmetic number, because the mean of its divisors is an integer number (10813826128).

Almost surely, 2^40165639891 is an apocalyptic number.

40165639891 is a deficient number, since it is larger than the sum of its proper divisors (3089664621).

40165639891 is a wasteful number, since it uses less digits than its factorization.

40165639891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3089664620.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The spelling of 40165639891 in words is "forty billion, one hundred sixty-five million, six hundred thirty-nine thousand, eight hundred ninety-one".