21252032125 has 8 divisors (see below), whose sum is σ = 26522536248. Its totient is φ = 17001625600.

The previous prime is 21252032107. The next prime is 21252032147. The reversal of 21252032125 is 52123025212.

It can be written as a sum of positive squares in 4 ways, for example, as 528126361 + 20723905764 = 22981^2 + 143958^2 .

It is not a de Polignac number, because 21252032125 - 2⁵ = 21252032093 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21252032125.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 85008004 + ... + 85008253.

It is an arithmetic number, because the mean of its divisors is an integer number (3315317031).

Almost surely, 2^21252032125 is an apocalyptic number.

21252032125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21252032125 is a deficient number, since it is larger than the sum of its proper divisors (5270504123).

21252032125 is an equidigital number, since it uses as much as digits as its factorization.

21252032125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170016272 (or 170016262 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21252032125 its reverse (52123025212), we get a palindrome (73375057337).

The spelling of 21252032125 in words is "twenty-one billion, two hundred fifty-two million, thirty-two thousand, one hundred twenty-five".