221212203220 has 48 divisors (see below), whose sum is σ = 465336038160. Its totient is φ = 88334465024.

The previous prime is 221212203131. The next prime is 221212203229. The reversal of 221212203220 is 22302212122.

It can be written as a sum of positive squares in 8 ways, for example, as 14227241284 + 206984961936 = 119278^2 + 454956^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221212203229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39018546 + ... + 39024214.

It is an arithmetic number, because the mean of its divisors is an integer number (9694500795).

Almost surely, 2^221212203220 is an apocalyptic number.

221212203220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221212203220 is an abundant number, since it is smaller than the sum of its proper divisors (244123834940).

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

221212203220 is a wasteful number, since it uses less digits than its factorization.

221212203220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8652 (or 8650 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 221212203220 its reverse (22302212122), we get a palindrome (243514415342).

The spelling of 221212203220 in words is "two hundred twenty-one billion, two hundred twelve million, two hundred three thousand, two hundred twenty".