21051230225 has 12 divisors (see below), whose sum is σ = 26105496924. Its totient is φ = 16839712320.

The previous prime is 21051230209. The next prime is 21051230227. The reversal of 21051230225 is 52203215012.

It can be written as a sum of positive squares in 6 ways, for example, as 94614529 + 20956615696 = 9727^2 + 144764^2 .

It is not a de Polignac number, because 21051230225 - 2⁴ = 21051230209 is a prime.

It is a super-3 number, since 3×21051230225³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21051230225.

It is not an unprimeable number, because it can be changed into a prime (21051230227) 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, 447527 + ... + 492323.

It is an arithmetic number, because the mean of its divisors is an integer number (2175458077).

Almost surely, 2^21051230225 is an apocalyptic number.

21051230225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21051230225 is a deficient number, since it is larger than the sum of its proper divisors (5054266699).

21051230225 is a wasteful number, since it uses less digits than its factorization.

21051230225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63604 (or 63599 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

Adding to 21051230225 its reverse (52203215012), we get a palindrome (73254445237).

The spelling of 21051230225 in words is "twenty-one billion, fifty-one million, two hundred thirty thousand, two hundred twenty-five".