1211021201220 has 48 divisors (see below), whose sum is σ = 3391025964480. Its totient is φ = 322923120256.

The previous prime is 1211021201171. The next prime is 1211021201237. The reversal of 1211021201220 is 221021201121.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1211021201220.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 761899 + ... + 1732781.

It is an arithmetic number, because the mean of its divisors is an integer number (70646374260).

Almost surely, 2^{1211021201220} is an apocalyptic number.

1211021201220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211021201220 is an abundant number, since it is smaller than the sum of its proper divisors (2180004763260).

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

1211021201220 is a wasteful number, since it uses less digits than its factorization.

1211021201220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991684 (or 991682 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1211021201220 its reverse (221021201121), we get a palindrome (1432042402341).

Subtracting from 1211021201220 its reverse (221021201121), we obtain a palindrome (990000000099).

The spelling of 1211021201220 in words is "one trillion, two hundred eleven billion, twenty-one million, two hundred one thousand, two hundred twenty".