20525221 has 4 divisors (see below), whose sum is σ = 20542572. Its totient is φ = 20507872.

The previous prime is 20525213. The next prime is 20525231. The reversal of 20525221 is 12252502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8352100 + 12173121 = 2890^2 + 3489^2 .

It is a cyclic number.

It is not a de Polignac number, because 20525221 - 2³ = 20525213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20525231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6760 + ... + 9313.

It is an arithmetic number, because the mean of its divisors is an integer number (5135643).

Almost surely, 2^20525221 is an apocalyptic number.

It is an amenable number.

20525221 is a deficient number, since it is larger than the sum of its proper divisors (17351).

20525221 is a wasteful number, since it uses less digits than its factorization.

20525221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17350.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 20525221 is about 4530.4769064636. The cubic root of 20525221 is about 273.7973753693.

Adding to 20525221 its reverse (12252502), we get a palindrome (32777723).

The spelling of 20525221 in words is "twenty million, five hundred twenty-five thousand, two hundred twenty-one".