1211121011220 has 48 divisors (see below), whose sum is σ = 3391201271808. Its totient is φ = 322959656320.

The previous prime is 1211121011213. The next prime is 1211121011231. The reversal of 1211121011220 is 221101211121.

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 1211121011220.

It is a congruent number.

It is an unprimeable number.

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, 3810010 + ... + 4115630.

It is an arithmetic number, because the mean of its divisors is an integer number (70650026496).

Almost surely, 2^{1211121011220} is an apocalyptic number.

1211121011220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211121011220 is an abundant number, since it is smaller than the sum of its proper divisors (2180080260588).

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

1211121011220 is a wasteful number, since it uses less digits than its factorization.

1211121011220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371680 (or 371678 counting only the distinct ones).

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

Adding to 1211121011220 its reverse (221101211121), we get a palindrome (1432222222341).

The spelling of 1211121011220 in words is "one trillion, two hundred eleven billion, one hundred twenty-one million, eleven thousand, two hundred twenty".