1221221022020 has 24 divisors (see below), whose sum is σ = 2575570869144. Its totient is φ = 486391890176.

The previous prime is 1221221021921. The next prime is 1221221022029. The reversal of 1221221022020 is 202201221221.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 169890703684 + 1051330318336 = 412178^2 + 1025344^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1221221022020.

It is not an unprimeable number, because it can be changed into a prime (1221221022029) 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, 131027639 + ... + 131036958.

It is an arithmetic number, because the mean of its divisors is an integer number (107315452881).

Almost surely, 2^{1221221022020} is an apocalyptic number.

1221221022020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221221022020 is an abundant number, since it is smaller than the sum of its proper divisors (1354349847124).

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

1221221022020 is a wasteful number, since it uses less digits than its factorization.

1221221022020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262064839 (or 262064837 counting only the distinct ones).

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

Adding to 1221221022020 its reverse (202201221221), we get a palindrome (1423422243241).

The spelling of 1221221022020 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, twenty-two thousand, twenty".