1221012020100 has 72 divisors (see below), whose sum is σ = 3533633430208. Its totient is φ = 325525910400.

The previous prime is 1221012020099. The next prime is 1221012020113. The reversal of 1221012020100 is 10202101221.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 788322 + ... + 1750278.

Almost surely, 2^{1221012020100} is an apocalyptic number.

1221012020100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221012020100 is an abundant number, since it is smaller than the sum of its proper divisors (2312621410108).

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

1221012020100 is a wasteful number, since it uses less digits than its factorization.

1221012020100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 966205 (or 966198 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 1221012020100 its reverse (10202101221), we get a palindrome (1231214121321).

The spelling of 1221012020100 in words is "one trillion, two hundred twenty-one billion, twelve million, twenty thousand, one hundred".