20855801 has 4 divisors (see below), whose sum is σ = 20867472. Its totient is φ = 20844132.

The previous prime is 20855789. The next prime is 20855831. The reversal of 20855801 is 10855802.

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, 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 20855801 - 2¹⁴ = 20839417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20855831) 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 3 ways as a sum of consecutive naturals, for example, 2531 + ... + 6936.

It is an arithmetic number, because the mean of its divisors is an integer number (5216868).

Almost surely, 2^20855801 is an apocalyptic number.

It is an amenable number.

20855801 is a deficient number, since it is larger than the sum of its proper divisors (11671).

20855801 is an equidigital number, since it uses as much as digits as its factorization.

20855801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11670.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 20855801 is about 4566.8151922319. The cubic root of 20855801 is about 275.2594840052.

Subtracting from 20855801 its reverse (10855802), we obtain a palindrome (9999999).

The spelling of 20855801 in words is "twenty million, eight hundred fifty-five thousand, eight hundred one".