21011105225 has 24 divisors (see below), whose sum is σ = 28480364640. Its totient is φ = 15249584000.

The previous prime is 21011105209. The next prime is 21011105249. The reversal of 21011105225 is 52250111012.

It is not a de Polignac number, because 21011105225 - 2⁴ = 21011105209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21011105197 and 21011105206.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 57221 + ... + 212829.

It is an arithmetic number, because the mean of its divisors is an integer number (1186681860).

Almost surely, 2^21011105225 is an apocalyptic number.

21011105225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21011105225 is a deficient number, since it is larger than the sum of its proper divisors (7469259415).

21011105225 is a wasteful number, since it uses less digits than its factorization.

21011105225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156121 (or 156116 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 20.

Adding to 21011105225 its reverse (52250111012), we get a palindrome (73261216237).

The spelling of 21011105225 in words is "twenty-one billion, eleven million, one hundred five thousand, two hundred twenty-five".