21115504143225 has 72 divisors (see below), whose sum is σ = 39126984563160. Its totient is φ = 10872541532160.

The previous prime is 21115504143091. The next prime is 21115504143241. The reversal of 21115504143225 is 52234140551112.

21115504143225 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 5 + 504 + 143 + 2 + 2 + 5 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 8909222068224 + 12206282075001 = 2984832^2 + 3493749^2 .

It is not a de Polignac number, because 21115504143225 - 2⁹ = 21115504142713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21115504143225.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 104932407 + ... + 105133443.

It is an arithmetic number, because the mean of its divisors is an integer number (543430341155).

Almost surely, 2^{21115504143225} is an apocalyptic number.

21115504143225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21115504143225 is a deficient number, since it is larger than the sum of its proper divisors (18011480419935).

21115504143225 is a wasteful number, since it uses less digits than its factorization.

21115504143225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217179 (or 217171 counting only the distinct ones).

The product of its (nonzero) digits is 48000, while the sum is 36.

Adding to 21115504143225 its reverse (52234140551112), we get a palindrome (73349644694337).

The spelling of 21115504143225 in words is "twenty-one trillion, one hundred fifteen billion, five hundred four million, one hundred forty-three thousand, two hundred twenty-five".