20855579 has 4 divisors (see below), whose sum is σ = 20864760. Its totient is φ = 20846400.

The previous prime is 20855563. The next prime is 20855581. The reversal of 20855579 is 97555802.

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, and also an emirpimes, since its reverse is a distinct semiprime: 97555802 = 2 ⋅48777901.

It is a cyclic number.

It is not a de Polignac number, because 20855579 - 2⁴ = 20855563 is a prime.

It is a Duffinian 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, 1604 + ... + 6654.

It is an arithmetic number, because the mean of its divisors is an integer number (5216190).

Almost surely, 2^20855579 is an apocalyptic number.

20855579 is a deficient number, since it is larger than the sum of its proper divisors (9181).

20855579 is an equidigital number, since it uses as much as digits as its factorization.

20855579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9180.

The product of its (nonzero) digits is 126000, while the sum is 41.

The square root of 20855579 is about 4566.7908863884. The cubic root of 20855579 is about 275.2585073333.

The spelling of 20855579 in words is "twenty million, eight hundred fifty-five thousand, five hundred seventy-nine".