1221201111020 has 24 divisors (see below), whose sum is σ = 2797660727568. Its totient is φ = 444073131200.

The previous prime is 1221201110999. The next prime is 1221201111029. The reversal of 1221201111020 is 201111021221.

It is a junction number, because it is equal to n+sod(n) for n = 1221201110986 and 1221201111004.

It is not an unprimeable number, because it can be changed into a prime (1221201111029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2775456851 + ... + 2775457290.

It is an arithmetic number, because the mean of its divisors is an integer number (116569196982).

Almost surely, 2^{1221201111020} is an apocalyptic number.

1221201111020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221201111020 is an abundant number, since it is smaller than the sum of its proper divisors (1576459616548).

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

1221201111020 is a wasteful number, since it uses less digits than its factorization.

1221201111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5550914161 (or 5550914159 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221201111020 its reverse (201111021221), we get a palindrome (1422312132241).

The spelling of 1221201111020 in words is "one trillion, two hundred twenty-one billion, two hundred one million, one hundred eleven thousand, twenty".