1221031021100 has 72 divisors (see below), whose sum is σ = 2897039452608. Its totient is φ = 443008820800.

The previous prime is 1221031021081. The next prime is 1221031021139. The reversal of 1221031021100 is 11201301221.

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 23 ways as a sum of consecutive naturals, for example, 765554 + ... + 1740153.

It is an arithmetic number, because the mean of its divisors is an integer number (40236659064).

Almost surely, 2^{1221031021100} is an apocalyptic number.

1221031021100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221031021100 is an abundant number, since it is smaller than the sum of its proper divisors (1676008431508).

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

1221031021100 is a wasteful number, since it uses less digits than its factorization.

1221031021100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2506175 (or 2506168 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 1221031021100 its reverse (11201301221), we get a palindrome (1232232322321).

The spelling of 1221031021100 in words is "one trillion, two hundred twenty-one billion, thirty-one million, twenty-one thousand, one hundred".