1211021111220 has 24 divisors (see below), whose sum is σ = 3390859111584. Its totient is φ = 322938962976.

The previous prime is 1211021111207. The next prime is 1211021111221. The reversal of 1211021111220 is 221111201121.

It is a happy number.

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 1211021111220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211021111221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10091842534 + ... + 10091842653.

It is an arithmetic number, because the mean of its divisors is an integer number (141285796316).

Almost surely, 2^{1211021111220} is an apocalyptic number.

1211021111220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211021111220 is an abundant number, since it is smaller than the sum of its proper divisors (2179838000364).

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

1211021111220 is a wasteful number, since it uses less digits than its factorization.

1211021111220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20183685199 (or 20183685197 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211021111220 its reverse (221111201121), we get a palindrome (1432132312341).

The spelling of 1211021111220 in words is "one trillion, two hundred eleven billion, twenty-one million, one hundred eleven thousand, two hundred twenty".