20855555 has 8 divisors (see below), whose sum is σ = 28601952. Its totient is φ = 14300928.

The previous prime is 20855537. The next prime is 20855563. The reversal of 20855555 is 55555802.

It is a happy number.

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 20855555 - 2⁶ = 20855491 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35), and also a Moran number because the ratio is a prime number: 595873 = 20855555 / (2 + 0 + 8 + 5 + 5 + 5 + 5 + 5).

It is a Duffinian number.

20855555 is a modest number, since divided by 5555 gives 2085 as remainder.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 297902 + ... + 297971.

It is an arithmetic number, because the mean of its divisors is an integer number (3575244).

Almost surely, 2^20855555 is an apocalyptic number.

20855555 is a deficient number, since it is larger than the sum of its proper divisors (7746397).

20855555 is an equidigital number, since it uses as much as digits as its factorization.

20855555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 595885.

The product of its (nonzero) digits is 50000, while the sum is 35.

The square root of 20855555 is about 4566.7882587219. The cubic root of 20855555 is about 275.2584017467.

The spelling of 20855555 in words is "twenty million, eight hundred fifty-five thousand, five hundred fifty-five".