21202120122100 has 36 divisors (see below), whose sum is σ = 46206062521164. Its totient is φ = 8444449550080.

The previous prime is 21202120122041. The next prime is 21202120122103. The reversal of 21202120122100 is 122102120212.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 132312607504 + 21069807514596 = 363748^2 + 4590186^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202120122103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 454957819 + ... + 455004418.

It is an arithmetic number, because the mean of its divisors is an integer number (1283501736699).

Almost surely, 2^{21202120122100} is an apocalyptic number.

21202120122100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202120122100 is an abundant number, since it is smaller than the sum of its proper divisors (25003942399064).

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

21202120122100 is a wasteful number, since it uses less digits than its factorization.

21202120122100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909962484 (or 909962477 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21202120122100 its reverse (122102120212), we get a palindrome (21324222242312).

The spelling of 21202120122100 in words is "twenty-one trillion, two hundred two billion, one hundred twenty million, one hundred twenty-two thousand, one hundred".