25211421517 has 2 divisors, whose sum is σ = 25211421518. Its totient is φ = 25211421516.

The previous prime is 25211421497. The next prime is 25211421539. The reversal of 25211421517 is 71512411252.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15244593961 + 9966827556 = 123469^2 + 99834^2 .

It is a cyclic number.

It is not a de Polignac number, because 25211421517 - 2¹¹ = 25211419469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25211421577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12605710758 + 12605710759.

It is an arithmetic number, because the mean of its divisors is an integer number (12605710759).

Almost surely, 2^25211421517 is an apocalyptic number.

It is an amenable number.

25211421517 is a deficient number, since it is larger than the sum of its proper divisors (1).

25211421517 is an equidigital number, since it uses as much as digits as its factorization.

25211421517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5600, while the sum is 31.

Adding to 25211421517 its reverse (71512411252), we get a palindrome (96723832769).

The spelling of 25211421517 in words is "twenty-five billion, two hundred eleven million, four hundred twenty-one thousand, five hundred seventeen".