21205159225 has 12 divisors (see below), whose sum is σ = 26321507280. Its totient is φ = 16946637200.

The previous prime is 21205159193. The next prime is 21205159229. The reversal of 21205159225 is 52295150212.

It is not a de Polignac number, because 21205159225 - 2⁵ = 21205159193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21205159229) 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, 412495 + ... + 461044.

It is an arithmetic number, because the mean of its divisors is an integer number (2193458940).

Almost surely, 2^21205159225 is an apocalyptic number.

21205159225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21205159225 is a deficient number, since it is larger than the sum of its proper divisors (5116348055).

21205159225 is an equidigital number, since it uses as much as digits as its factorization.

21205159225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 874520 (or 874515 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 34.

The spelling of 21205159225 in words is "twenty-one billion, two hundred five million, one hundred fifty-nine thousand, two hundred twenty-five".