20887091 has 4 divisors (see below), whose sum is σ = 20958672. Its totient is φ = 20815512.

The previous prime is 20887079. The next prime is 20887109. The reversal of 20887091 is 19078802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19078802 = 2 ⋅9539401.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20887091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20887001) 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, 35351 + ... + 35936.

It is an arithmetic number, because the mean of its divisors is an integer number (5239668).

Almost surely, 2^20887091 is an apocalyptic number.

20887091 is a deficient number, since it is larger than the sum of its proper divisors (71581).

20887091 is an equidigital number, since it uses as much as digits as its factorization.

20887091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71580.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 20887091 is about 4570.2397092494. The cubic root of 20887091 is about 275.3970726716.

The spelling of 20887091 in words is "twenty million, eight hundred eighty-seven thousand, ninety-one".