21500111624225 has 12 divisors (see below), whose sum is σ = 28710918292476. Its totient is φ = 15877005506880.

The previous prime is 21500111624203. The next prime is 21500111624237. The reversal of 21500111624225 is 52242611100512.

It can be written as a sum of positive squares in 6 ways, for example, as 58099799521 + 21442011824704 = 241039^2 + 4630552^2 .

It is not a de Polignac number, because 21500111624225 - 2²⁶ = 21500044515361 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21500111624191 and 21500111624200.

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 11 ways as a sum of consecutive naturals, for example, 33077094482 + ... + 33077095131.

It is an arithmetic number, because the mean of its divisors is an integer number (2392576524373).

Almost surely, 2^{21500111624225} is an apocalyptic number.

21500111624225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21500111624225 is a deficient number, since it is larger than the sum of its proper divisors (7210806668251).

21500111624225 is a wasteful number, since it uses less digits than its factorization.

21500111624225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66154189636 (or 66154189631 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 32.

Adding to 21500111624225 its reverse (52242611100512), we get a palindrome (73742722724737).

The spelling of 21500111624225 in words is "twenty-one trillion, five hundred billion, one hundred eleven million, six hundred twenty-four thousand, two hundred twenty-five".