20855599 has 4 divisors (see below), whose sum is σ = 20864736. Its totient is φ = 20846464.

The previous prime is 20855581. The next prime is 20855603. The reversal of 20855599 is 99555802.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20855599 - 2¹⁵ = 20822831 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 (20855519) 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, 2127 + ... + 6799.

It is an arithmetic number, because the mean of its divisors is an integer number (5216184).

Almost surely, 2^20855599 is an apocalyptic number.

20855599 is a deficient number, since it is larger than the sum of its proper divisors (9137).

20855599 is an equidigital number, since it uses as much as digits as its factorization.

20855599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9136.

The product of its (nonzero) digits is 162000, while the sum is 43.

The square root of 20855599 is about 4566.7930761093. The cubic root of 20855599 is about 275.2585953220.

The spelling of 20855599 in words is "twenty million, eight hundred fifty-five thousand, five hundred ninety-nine".