21530431523225 has 12 divisors (see below), whose sum is σ = 26698920720720. Its totient is φ = 17223580294800.

The previous prime is 21530431523207. The next prime is 21530431523261. The reversal of 21530431523225 is 52232513403512.

It is not a de Polignac number, because 21530431523225 - 2³⁰ = 21529357781401 is a prime.

It is a Curzon number.

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, 18548555 + ... + 19675104.

It is an arithmetic number, because the mean of its divisors is an integer number (2224910060060).

Almost surely, 2^{21530431523225} is an apocalyptic number.

21530431523225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21530431523225 is a deficient number, since it is larger than the sum of its proper divisors (5168489197495).

21530431523225 is a wasteful number, since it uses less digits than its factorization.

21530431523225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38246200 (or 38246195 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 38.

Adding to 21530431523225 its reverse (52232513403512), we get a palindrome (73762944926737).

The spelling of 21530431523225 in words is "twenty-one trillion, five hundred thirty billion, four hundred thirty-one million, five hundred twenty-three thousand, two hundred twenty-five".