20899563 has 16 divisors (see below), whose sum is σ = 29441280. Its totient is φ = 13150944.

The previous prime is 20899559. The next prime is 20899573. The reversal of 20899563 is 36599802.

It is not a de Polignac number, because 20899563 - 2² = 20899559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20899513) 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 15 ways as a sum of consecutive naturals, for example, 20770 + ... + 21752.

It is an arithmetic number, because the mean of its divisors is an integer number (1840080).

Almost surely, 2^20899563 is an apocalyptic number.

20899563 is a deficient number, since it is larger than the sum of its proper divisors (8541717).

20899563 is a wasteful number, since it uses less digits than its factorization.

20899563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1378.

The product of its (nonzero) digits is 116640, while the sum is 42.

The square root of 20899563 is about 4571.6039854738. The cubic root of 20899563 is about 275.4518763598.

The spelling of 20899563 in words is "twenty million, eight hundred ninety-nine thousand, five hundred sixty-three".