1221001200100 has 72 divisors (see below), whose sum is σ = 3016114331328. Its totient is φ = 424696060800.

The previous prime is 1221001200079. The next prime is 1221001200131. The reversal of 1221001200100 is 10021001221.

It is a Harshad number since it is a multiple of its sum of digits (10).

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, 24105159 + ... + 24155758.

It is an arithmetic number, because the mean of its divisors is an integer number (41890476824).

Almost surely, 2^{1221001200100} is an apocalyptic number.

1221001200100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221001200100 is an abundant number, since it is smaller than the sum of its proper divisors (1795113131228).

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

1221001200100 is a wasteful number, since it uses less digits than its factorization.

1221001200100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48260965 (or 48260958 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 1221001200100 its reverse (10021001221), we get a palindrome (1231022201321).

The spelling of 1221001200100 in words is "one trillion, two hundred twenty-one billion, one million, two hundred thousand, one hundred".