21121220112100 has 36 divisors (see below), whose sum is σ = 47413497568500. Its totient is φ = 8157160869760.

The previous prime is 21121220112017. The next prime is 21121220112101. The reversal of 21121220112100 is 121102212112.

It can be written as a sum of positive squares in 6 ways, for example, as 1393622748324 + 19727597363776 = 1180518^2 + 4441576^2 .

It is a super-2 number, since 2×21121220112100² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121220112101) 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, 3641586775 + ... + 3641592574.

It is an arithmetic number, because the mean of its divisors is an integer number (1317041599125).

Almost surely, 2^{21121220112100} is an apocalyptic number.

21121220112100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121220112100 is an abundant number, since it is smaller than the sum of its proper divisors (26292277456400).

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

21121220112100 is a wasteful number, since it uses less digits than its factorization.

21121220112100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7283179392 (or 7283179385 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21121220112100 its reverse (121102212112), we get a palindrome (21242322324212).

The spelling of 21121220112100 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty million, one hundred twelve thousand, one hundred".