21202451225 has 12 divisors (see below), whose sum is σ = 26305104684. Its totient is φ = 16952886720.

The previous prime is 21202451191. The next prime is 21202451233. The reversal of 21202451225 is 52215420212.

It can be written as a sum of positive squares in 6 ways, for example, as 669567376 + 20532883849 = 25876^2 + 143293^2 .

It is not a de Polignac number, because 21202451225 - 2¹² = 21202447129 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21202451194 and 21202451203.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 178994 + ... + 272843.

It is an arithmetic number, because the mean of its divisors is an integer number (2192092057).

Almost surely, 2^21202451225 is an apocalyptic number.

21202451225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21202451225 is a deficient number, since it is larger than the sum of its proper divisors (5102653459).

21202451225 is a wasteful number, since it uses less digits than its factorization.

21202451225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453724 (or 453719 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 26.

Adding to 21202451225 its reverse (52215420212), we get a palindrome (73417871437).

The spelling of 21202451225 in words is "twenty-one billion, two hundred two million, four hundred fifty-one thousand, two hundred twenty-five".