21212303220 has 48 divisors (see below), whose sum is σ = 65993833920. Its totient is φ = 5656614048.

The previous prime is 21212303201. The next prime is 21212303221. The reversal of 21212303220 is 2230321212.

21212303220 is a `hidden beast` number, since 212 + 1 + 230 + 3 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21212303193 and 21212303202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212303221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19640482 + ... + 19641561.

It is an arithmetic number, because the mean of its divisors is an integer number (1374871540).

Almost surely, 2^21212303220 is an apocalyptic number.

21212303220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212303220 is an abundant number, since it is smaller than the sum of its proper divisors (44781530700).

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

21212303220 is a wasteful number, since it uses less digits than its factorization.

21212303220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39282061 (or 39282053 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21212303220 its reverse (2230321212), we get a palindrome (23442624432).

The spelling of 21212303220 in words is "twenty-one billion, two hundred twelve million, three hundred three thousand, two hundred twenty".