21320125525 has 6 divisors (see below), whose sum is σ = 26436955682. Its totient is φ = 17056100400.

The previous prime is 21320125523. The next prime is 21320125529. The reversal of 21320125525 is 52552102312.

It can be written as a sum of positive squares in 3 ways, for example, as 456634161 + 20863491364 = 21369^2 + 144442^2 .

It is not a de Polignac number, because 21320125525 - 2¹ = 21320125523 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21320125493 and 21320125502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320125523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 426402486 + ... + 426402535.

Almost surely, 2^21320125525 is an apocalyptic number.

21320125525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21320125525 is a deficient number, since it is larger than the sum of its proper divisors (5116830157).

21320125525 is an equidigital number, since it uses as much as digits as its factorization.

21320125525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 852805031 (or 852805026 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21320125525 its reverse (52552102312), we get a palindrome (73872227837).

The spelling of 21320125525 in words is "twenty-one billion, three hundred twenty million, one hundred twenty-five thousand, five hundred twenty-five".