20042521 has 2 divisors, whose sum is σ = 20042522. Its totient is φ = 20042520.

The previous prime is 20042513. The next prime is 20042527. The reversal of 20042521 is 12524002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10208025 + 9834496 = 3195^2 + 3136^2 .

It is a cyclic number.

It is not a de Polignac number, because 20042521 - 2³ = 20042513 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20042495 and 20042504.

It is not a weakly prime, because it can be changed into another prime (20042527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10021260 + 10021261.

It is an arithmetic number, because the mean of its divisors is an integer number (10021261).

Almost surely, 2^20042521 is an apocalyptic number.

It is an amenable number.

20042521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20042521 is an equidigital number, since it uses as much as digits as its factorization.

20042521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 20042521 is about 4476.8874231993. The cubic root of 20042521 is about 271.6339917460.

Adding to 20042521 its reverse (12524002), we get a palindrome (32566523).

The spelling of 20042521 in words is "twenty million, forty-two thousand, five hundred twenty-one".