1221012000020 has 24 divisors (see below), whose sum is σ = 2564885983968. Its totient is φ = 488259888800.

The previous prime is 1221012000017. The next prime is 1221012000037. The reversal of 1221012000020 is 200002101221.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1221011999965 and 1221012000010.

It is a congruent number.

It is an unprimeable number.

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, 8987846 + ... + 9122685.

It is an arithmetic number, because the mean of its divisors is an integer number (106870249332).

Almost surely, 2^{1221012000020} is an apocalyptic number.

1221012000020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221012000020 is an abundant number, since it is smaller than the sum of its proper divisors (1343873983948).

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

1221012000020 is a wasteful number, since it uses less digits than its factorization.

1221012000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18113911 (or 18113909 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 1221012000020 its reverse (200002101221), we get a palindrome (1421014101241).

The spelling of 1221012000020 in words is "one trillion, two hundred twenty-one billion, twelve million, twenty", and thus it is an aban number.