1211221202220 has 72 divisors (see below), whose sum is σ = 3679147967040. Its totient is φ = 322543061760.

The previous prime is 1211221202209. The next prime is 1211221202273. The reversal of 1211221202220 is 222021221121.

It is a happy number.

1211221202220 is a `hidden beast` number, since 1 + 21 + 1 + 221 + 202 + 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 = 1211221202193 and 1211221202202.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4550001 + ... + 4808840.

It is an arithmetic number, because the mean of its divisors is an integer number (51099277320).

Almost surely, 2^{1211221202220} is an apocalyptic number.

1211221202220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211221202220 is an abundant number, since it is smaller than the sum of its proper divisors (2467926764820).

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

1211221202220 is a wasteful number, since it uses less digits than its factorization.

1211221202220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9359575 (or 9359570 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1211221202220 its reverse (222021221121), we get a palindrome (1433242423341).

The spelling of 1211221202220 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred two thousand, two hundred twenty".