21321153225 has 18 divisors (see below), whose sum is σ = 38188554846. Its totient is φ = 11371281600.

The previous prime is 21321153209. The next prime is 21321153251. The reversal of 21321153225 is 52235112312.

21321153225 is a `hidden beast` number, since 2 + 1 + 321 + 15 + 322 + 5 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 6406881849 + 14914271376 = 80043^2 + 122124^2 .

It is not a de Polignac number, because 21321153225 - 2⁴ = 21321153209 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 47380116 + ... + 47380565.

Almost surely, 2^21321153225 is an apocalyptic number.

21321153225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21321153225 is a deficient number, since it is larger than the sum of its proper divisors (16867401621).

21321153225 is a wasteful number, since it uses less digits than its factorization.

21321153225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94760697 (or 94760689 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

Adding to 21321153225 its reverse (52235112312), we get a palindrome (73556265537).

The spelling of 21321153225 in words is "twenty-one billion, three hundred twenty-one million, one hundred fifty-three thousand, two hundred twenty-five".