20855569 has 4 divisors (see below), whose sum is σ = 23834944. Its totient is φ = 17876196.

The previous prime is 20855563. The next prime is 20855581. The reversal of 20855569 is 96555802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20855569 - 2⁵ = 20855537 is a prime.

It is a super-2 number, since 2×20855569² = 869909516627522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20855563) 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 3 ways as a sum of consecutive naturals, for example, 1489677 + ... + 1489690.

It is an arithmetic number, because the mean of its divisors is an integer number (5958736).

Almost surely, 2^20855569 is an apocalyptic number.

It is an amenable number.

20855569 is a deficient number, since it is larger than the sum of its proper divisors (2979375).

20855569 is an equidigital number, since it uses as much as digits as its factorization.

20855569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2979374.

The product of its (nonzero) digits is 108000, while the sum is 40.

The square root of 20855569 is about 4566.7897915275. The cubic root of 20855569 is about 275.2584633389.

The spelling of 20855569 in words is "twenty million, eight hundred fifty-five thousand, five hundred sixty-nine".