25217561 has 2 divisors, whose sum is σ = 25217562. Its totient is φ = 25217560.

The previous prime is 25217557. The next prime is 25217623. The reversal of 25217561 is 16571252.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25200400 + 17161 = 5020^2 + 131^2 .

It is a cyclic number.

It is not a de Polignac number, because 25217561 - 2² = 25217557 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (25217761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12608780 + 12608781.

It is an arithmetic number, because the mean of its divisors is an integer number (12608781).

Almost surely, 2^25217561 is an apocalyptic number.

It is an amenable number.

25217561 is a deficient number, since it is larger than the sum of its proper divisors (1).

25217561 is an equidigital number, since it uses as much as digits as its factorization.

25217561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4200, while the sum is 29.

The square root of 25217561 is about 5021.7089720532. The cubic root of 25217561 is about 293.2475281341.

The spelling of 25217561 in words is "twenty-five million, two hundred seventeen thousand, five hundred sixty-one".