20111211011220 has 144 divisors (see below), whose sum is σ = 65741570415360. Its totient is φ = 4580252925696.

The previous prime is 20111211011189. The next prime is 20111211011233. The reversal of 20111211011220 is 2211011211102.

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 20111211011220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11533180 + ... + 13161939.

It is an arithmetic number, because the mean of its divisors is an integer number (456538683440).

Almost surely, 2^{20111211011220} is an apocalyptic number.

20111211011220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20111211011220 is an abundant number, since it is smaller than the sum of its proper divisors (45630359404140).

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

20111211011220 is a wasteful number, since it uses less digits than its factorization.

20111211011220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24695422 (or 24695413 counting only the distinct ones).

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

Adding to 20111211011220 its reverse (2211011211102), we get a palindrome (22322222222322).

The spelling of 20111211011220 in words is "twenty trillion, one hundred eleven billion, two hundred eleven million, eleven thousand, two hundred twenty".