20887559 has 16 divisors (see below), whose sum is σ = 26474496. Its totient is φ = 16005600.

The previous prime is 20887549. The next prime is 20887567. The reversal of 20887559 is 95578802.

It is a cyclic number.

It is not a de Polignac number, because 20887559 - 2²⁴ = 4110343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20887549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2474 + ... + 6920.

It is an arithmetic number, because the mean of its divisors is an integer number (1654656).

Almost surely, 2^20887559 is an apocalyptic number.

20887559 is a deficient number, since it is larger than the sum of its proper divisors (5586937).

20887559 is a wasteful number, since it uses less digits than its factorization.

20887559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4526.

The product of its (nonzero) digits is 201600, while the sum is 44.

The square root of 20887559 is about 4570.2909097781. The cubic root of 20887559 is about 275.3991295220.

The spelling of 20887559 in words is "twenty million, eight hundred eighty-seven thousand, five hundred fifty-nine".