20312220 has 96 divisors (see below), whose sum is σ = 60963840. Its totient is φ = 5040640.

The previous prime is 20312219. The next prime is 20312221. The reversal of 20312220 is 2221302.

It is an interprime number because it is at equal distance from previous prime (20312219) and next prime (20312221).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20312196 and 20312205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20312221) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 56401 + ... + 56759.

It is an arithmetic number, because the mean of its divisors is an integer number (635040).

Almost surely, 2^20312220 is an apocalyptic number.

20312220 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 20312220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30481920).

20312220 is an abundant number, since it is smaller than the sum of its proper divisors (40651620).

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

20312220 is a wasteful number, since it uses less digits than its factorization.

20312220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435 (or 433 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 20312220 is about 4506.9080310119. The cubic root of 20312220 is about 272.8469670569.

Adding to 20312220 its reverse (2221302), we get a palindrome (22533522).

The spelling of 20312220 in words is "twenty million, three hundred twelve thousand, two hundred twenty".