25011721517 has 2 divisors, whose sum is σ = 25011721518. Its totient is φ = 25011721516.

The previous prime is 25011721447. The next prime is 25011721523. The reversal of 25011721517 is 71512711052.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23439916201 + 1571805316 = 153101^2 + 39646^2 .

It is a cyclic number.

It is not a de Polignac number, because 25011721517 - 2¹⁰ = 25011720493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25013721517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12505860758 + 12505860759.

It is an arithmetic number, because the mean of its divisors is an integer number (12505860759).

Almost surely, 2^25011721517 is an apocalyptic number.

It is an amenable number.

25011721517 is a deficient number, since it is larger than the sum of its proper divisors (1).

25011721517 is an equidigital number, since it uses as much as digits as its factorization.

25011721517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4900, while the sum is 32.

The spelling of 25011721517 in words is "twenty-five billion, eleven million, seven hundred twenty-one thousand, five hundred seventeen".