21020225225 has 12 divisors (see below), whose sum is σ = 26069366796. Its totient is φ = 16813414080.

The previous prime is 21020225201. The next prime is 21020225249. The reversal of 21020225225 is 52252202012.

It is an interprime number because it is at equal distance from previous prime (21020225201) and next prime (21020225249).

It can be written as a sum of positive squares in 6 ways, for example, as 61293241 + 20958931984 = 7829^2 + 144772^2 .

It is not a de Polignac number, because 21020225225 - 2³² = 16725257929 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020225225.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 93359 + ... + 225291.

It is an arithmetic number, because the mean of its divisors is an integer number (2172447233).

Almost surely, 2^21020225225 is an apocalyptic number.

21020225225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21020225225 is a deficient number, since it is larger than the sum of its proper divisors (5049141571).

21020225225 is a wasteful number, since it uses less digits than its factorization.

21020225225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138316 (or 138311 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 23.

Adding to 21020225225 its reverse (52252202012), we get a palindrome (73272427237).

The spelling of 21020225225 in words is "twenty-one billion, twenty million, two hundred twenty-five thousand, two hundred twenty-five".