20818573 has 4 divisors (see below), whose sum is σ = 20905920. Its totient is φ = 20731228.

The previous prime is 20818571. The next prime is 20818597. The reversal of 20818573 is 37581802.

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.

It is a cyclic number.

It is not a de Polignac number, because 20818573 - 2¹ = 20818571 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 (20818571) 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, 43315 + ... + 43792.

It is an arithmetic number, because the mean of its divisors is an integer number (5226480).

Almost surely, 2^20818573 is an apocalyptic number.

It is an amenable number.

20818573 is a deficient number, since it is larger than the sum of its proper divisors (87347).

20818573 is an equidigital number, since it uses as much as digits as its factorization.

20818573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87346.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 20818573 is about 4562.7374458761. The cubic root of 20818573 is about 275.0956053259.

It can be divided in two parts, 208 and 18573, that added together give a palindrome (18781).

The spelling of 20818573 in words is "twenty million, eight hundred eighteen thousand, five hundred seventy-three".