21234200225 has 18 divisors (see below), whose sum is σ = 30629252214. Its totient is φ = 14560593600.

The previous prime is 21234200219. The next prime is 21234200227. The reversal of 21234200225 is 52200243212.

It can be written as a sum of positive squares in 3 ways, for example, as 394101904 + 20840098321 = 19852^2 + 144361^2 .

It is not a de Polignac number, because 21234200225 - 2⁴ = 21234200209 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 21234200225.

It is not an unprimeable number, because it can be changed into a prime (21234200227) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 8665796 + ... + 8668245.

It is an arithmetic number, because the mean of its divisors is an integer number (1701625123).

Almost surely, 2^21234200225 is an apocalyptic number.

21234200225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21234200225 is a deficient number, since it is larger than the sum of its proper divisors (9395051989).

21234200225 is a wasteful number, since it uses less digits than its factorization.

21234200225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17334065 (or 17334053 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

Adding to 21234200225 its reverse (52200243212), we get a palindrome (73434443437).

The spelling of 21234200225 in words is "twenty-one billion, two hundred thirty-four million, two hundred thousand, two hundred twenty-five".