20125517 has 2 divisors, whose sum is σ = 20125518. Its totient is φ = 20125516.

The previous prime is 20125513. The next prime is 20125519. The reversal of 20125517 is 71552102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16924996 + 3200521 = 4114^2 + 1789^2 .

It is a cyclic number.

It is not a de Polignac number, because 20125517 - 2² = 20125513 is a prime.

Together with 20125519, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20125492 and 20125501.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20125513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10062758 + 10062759.

It is an arithmetic number, because the mean of its divisors is an integer number (10062759).

Almost surely, 2^20125517 is an apocalyptic number.

It is an amenable number.

20125517 is a deficient number, since it is larger than the sum of its proper divisors (1).

20125517 is an equidigital number, since it uses as much as digits as its factorization.

20125517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 20125517 is about 4486.1472334287. The cubic root of 20125517 is about 272.0084204789.

Adding to 20125517 its reverse (71552102), we get a palindrome (91677619).

The spelling of 20125517 in words is "twenty million, one hundred twenty-five thousand, five hundred seventeen".