20818820 has 48 divisors (see below), whose sum is σ = 48057408. Its totient is φ = 7512960.

The previous prime is 20818789. The next prime is 20818859. The reversal of 20818820 is 2881802.

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 15 ways as a sum of consecutive naturals, for example, 37787 + ... + 38333.

It is an arithmetic number, because the mean of its divisors is an integer number (1001196).

Almost surely, 2^20818820 is an apocalyptic number.

20818820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20818820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24028704).

20818820 is an abundant number, since it is smaller than the sum of its proper divisors (27238588).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20818820 is a wasteful number, since it uses less digits than its factorization.

20818820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 740 (or 738 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 29.

The square root of 20818820 is about 4562.7645128803. The cubic root of 20818820 is about 275.0966932702.

It can be divided in two parts, 2081 and 8820, that added together give a palindrome (10901).

The spelling of 20818820 in words is "twenty million, eight hundred eighteen thousand, eight hundred twenty".