21421322525 has 6 divisors (see below), whose sum is σ = 26562439962. Its totient is φ = 17137058000.

The previous prime is 21421322519. The next prime is 21421322609. The reversal of 21421322525 is 52522312412.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 111746041 + 21309576484 = 10571^2 + 145978^2 .

It is not a de Polignac number, because 21421322525 - 2⁸ = 21421322269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 428426426 + ... + 428426475.

It is an arithmetic number, because the mean of its divisors is an integer number (4427073327).

Almost surely, 2^21421322525 is an apocalyptic number.

21421322525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21421322525 is a deficient number, since it is larger than the sum of its proper divisors (5141117437).

21421322525 is an equidigital number, since it uses as much as digits as its factorization.

21421322525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856852911 (or 856852906 counting only the distinct ones).

The product of its digits is 9600, while the sum is 29.

Adding to 21421322525 its reverse (52522312412), we get a palindrome (73943634937).

The spelling of 21421322525 in words is "twenty-one billion, four hundred twenty-one million, three hundred twenty-two thousand, five hundred twenty-five".