20021855 has 8 divisors (see below), whose sum is σ = 27458592. Its totient is φ = 13729248.

The previous prime is 20021851. The next prime is 20021873. The reversal of 20021855 is 55812002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20021855 - 2² = 20021851 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20021855.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 285992 + ... + 286061.

It is an arithmetic number, because the mean of its divisors is an integer number (3432324).

Almost surely, 2^20021855 is an apocalyptic number.

20021855 is a deficient number, since it is larger than the sum of its proper divisors (7436737).

20021855 is an equidigital number, since it uses as much as digits as its factorization.

20021855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572065.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 20021855 is about 4474.5787511228. The cubic root of 20021855 is about 271.5405983287.

Adding to 20021855 its reverse (55812002), we get a palindrome (75833857).

The spelling of 20021855 in words is "twenty million, twenty-one thousand, eight hundred fifty-five".