40787891 has 4 divisors (see below), whose sum is σ = 42194400. Its totient is φ = 39381384.

The previous prime is 40787797. The next prime is 40787921. The reversal of 40787891 is 19878704.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40787891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40787291) 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, 703211 + ... + 703268.

It is an arithmetic number, because the mean of its divisors is an integer number (10548600).

Almost surely, 2^40787891 is an apocalyptic number.

40787891 is a deficient number, since it is larger than the sum of its proper divisors (1406509).

40787891 is a wasteful number, since it uses less digits than its factorization.

40787891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1406508.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 40787891 is about 6386.5398299862. The cubic root of 40787891 is about 344.2260632113.

The spelling of 40787891 in words is "forty million, seven hundred eighty-seven thousand, eight hundred ninety-one".