1221220212020 has 48 divisors (see below), whose sum is σ = 2732078196288. Its totient is φ = 456932897280.

The previous prime is 1221220211971. The next prime is 1221220212101. The reversal of 1221220212020 is 202120221221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 1221220212020.

It is a congruent number.

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, 10962446 + ... + 11073285.

It is an arithmetic number, because the mean of its divisors is an integer number (56918295756).

Almost surely, 2^{1221220212020} is an apocalyptic number.

1221220212020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221220212020 is an abundant number, since it is smaller than the sum of its proper divisors (1510857984268).

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

1221220212020 is a wasteful number, since it uses less digits than its factorization.

1221220212020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22035920 (or 22035918 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 1221220212020 its reverse (202120221221), we get a palindrome (1423340433241).

The spelling of 1221220212020 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, two hundred twelve thousand, twenty".