121221221012100 has 360 divisors, whose sum is σ = 433838930218848. Its totient is φ = 29032901107200.

The previous prime is 121221221012081. The next prime is 121221221012173. The reversal of 121221221012100 is 1210122122121.

121221221012100 is a `hidden beast` number, since 1 + 21 + 221 + 2 + 210 + 1 + 210 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 800529 + ... + 15591128.

Almost surely, 2^{121221221012100} is an apocalyptic number.

121221221012100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121221221012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216919465109424).

121221221012100 is an abundant number, since it is smaller than the sum of its proper divisors (312617709206748).

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

121221221012100 is a wasteful number, since it uses less digits than its factorization.

121221221012100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16391777 (or 16391761 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 121221221012100 its reverse (1210122122121), we get a palindrome (122431343134221).

The spelling of 121221221012100 in words is "one hundred twenty-one trillion, two hundred twenty-one billion, two hundred twenty-one million, twelve thousand, one hundred".