20125521 has 24 divisors (see below), whose sum is σ = 32159400. Its totient is φ = 12047616.

The previous prime is 20125519. The next prime is 20125537. The reversal of 20125521 is 12552102.

20125521 is a `hidden beast` number, since 20 + 125 + 521 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 9235521 + 10890000 = 3039^2 + 3300^2 .

It is not a de Polignac number, because 20125521 - 2¹ = 20125519 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20125494 and 20125503.

It is not an unprimeable number, because it can be changed into a prime (20125321) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2005 + ... + 6653.

It is an arithmetic number, because the mean of its divisors is an integer number (1339975).

Almost surely, 2^20125521 is an apocalyptic number.

It is an amenable number.

20125521 is a deficient number, since it is larger than the sum of its proper divisors (12033879).

20125521 is a wasteful number, since it uses less digits than its factorization.

20125521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4705 (or 4702 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 20125521 is about 4486.1476792455. The cubic root of 20125521 is about 272.0084384997.

Adding to 20125521 its reverse (12552102), we get a palindrome (32677623).

The spelling of 20125521 in words is "twenty million, one hundred twenty-five thousand, five hundred twenty-one".