1221101200100 has 72 divisors (see below), whose sum is σ = 2751603110088. Its totient is φ = 469999411200.

The previous prime is 1221101200091. The next prime is 1221101200127. The reversal of 1221101200100 is 10021011221.

It can be written as a sum of positive squares in 12 ways, for example, as 583182704896 + 637918495204 = 763664^2 + 798698^2 .

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, 1740629 + ... + 2339228.

Almost surely, 2^{1221101200100} is an apocalyptic number.

1221101200100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221101200100 is an abundant number, since it is smaller than the sum of its proper divisors (1530501909988).

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

1221101200100 is a wasteful number, since it uses less digits than its factorization.

1221101200100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4079985 (or 4079978 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1221101200100 its reverse (10021011221), we get a palindrome (1231122211321).

The spelling of 1221101200100 in words is "one trillion, two hundred twenty-one billion, one hundred one million, two hundred thousand, one hundred".