21121034225 has 12 divisors (see below), whose sum is σ = 27093189660. Its totient is φ = 16314177600.

The previous prime is 21121034189. The next prime is 21121034227. The reversal of 21121034225 is 52243012112.

It can be written as a sum of positive squares in 6 ways, for example, as 4831362064 + 16289672161 = 69508^2 + 127631^2 .

It is not a de Polignac number, because 21121034225 - 2⁶ = 21121034161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121034225.

It is not an unprimeable number, because it can be changed into a prime (21121034227) 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, 14565506 + ... + 14566955.

It is an arithmetic number, because the mean of its divisors is an integer number (2257765805).

Almost surely, 2^21121034225 is an apocalyptic number.

21121034225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21121034225 is a deficient number, since it is larger than the sum of its proper divisors (5972155435).

21121034225 is a wasteful number, since it uses less digits than its factorization.

21121034225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29132500 (or 29132495 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21121034225 its reverse (52243012112), we get a palindrome (73364046337).

The spelling of 21121034225 in words is "twenty-one billion, one hundred twenty-one million, thirty-four thousand, two hundred twenty-five".