1221012220020 has 48 divisors (see below), whose sum is σ = 3421470389568. Its totient is φ = 325352194560.

The previous prime is 1221012220009. The next prime is 1221012220061. The reversal of 1221012220020 is 200222101221.

It is a Harshad number since it is a multiple of its sum of digits (15).

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 15 ways as a sum of consecutive naturals, for example, 7767286 + ... + 7922925.

It is an arithmetic number, because the mean of its divisors is an integer number (71280633116).

Almost surely, 2^{1221012220020} is an apocalyptic number.

1221012220020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221012220020 is an abundant number, since it is smaller than the sum of its proper divisors (2200458169548).

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

1221012220020 is a wasteful number, since it uses less digits than its factorization.

1221012220020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15691520 (or 15691518 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 1221012220020 its reverse (200222101221), we get a palindrome (1421234321241).

The spelling of 1221012220020 in words is "one trillion, two hundred twenty-one billion, twelve million, two hundred twenty thousand, twenty".