20506220 has 48 divisors (see below), whose sum is σ = 49932288. Its totient is φ = 6928320.

The previous prime is 20506201. The next prime is 20506243. The reversal of 20506220 is 2260502.

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, 8909 + ... + 10971.

It is an arithmetic number, because the mean of its divisors is an integer number (1040256).

Almost surely, 2^20506220 is an apocalyptic number.

20506220 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 20506220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24966144).

20506220 is an abundant number, since it is smaller than the sum of its proper divisors (29426068).

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

20506220 is a wasteful number, since it uses less digits than its factorization.

20506220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2150 (or 2148 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 20506220 is about 4528.3794010661. The cubic root of 20506220 is about 273.7128609708.

Adding to 20506220 its reverse (2260502), we get a palindrome (22766722).

The spelling of 20506220 in words is "twenty million, five hundred six thousand, two hundred twenty".