1221221212020 has 96 divisors (see below), whose sum is σ = 3892022144640. Its totient is φ = 317716081920.

The previous prime is 1221221212007. The next prime is 1221221212037. The reversal of 1221221212020 is 202121221221.

It is a happy number.

1221221212020 is a `hidden beast` number, since 1 + 221 + 221 + 21 + 202 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221221211984 and 1221221212002.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 27557382 + ... + 27601661.

It is an arithmetic number, because the mean of its divisors is an integer number (40541897340).

Almost surely, 2^{1221221212020} is an apocalyptic number.

1221221212020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221221212020 is an abundant number, since it is smaller than the sum of its proper divisors (2670800932620).

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

1221221212020 is a wasteful number, since it uses less digits than its factorization.

1221221212020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55159102 (or 55159094 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221221212020 its reverse (202121221221), we get a palindrome (1423342433241).

The spelling of 1221221212020 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, twenty".