25661722316617 has 8 divisors (see below), whose sum is σ = 25666980676136. Its totient is φ = 25656464351232.

The previous prime is 25661722316569. The next prime is 25661722316653. The reversal of 25661722316617 is 71661322716652.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5370625486521 + 20291096830096 = 2317461^2 + 4504564^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25661722316617 - 2¹⁵ = 25661722283849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25661722316317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154140373 + ... + 154306765.

It is an arithmetic number, because the mean of its divisors is an integer number (3208372584517).

Almost surely, 2^{25661722316617} is an apocalyptic number.

It is an amenable number.

25661722316617 is a deficient number, since it is larger than the sum of its proper divisors (5258359519).

25661722316617 is a wasteful number, since it uses less digits than its factorization.

25661722316617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197067.

The product of its digits is 7620480, while the sum is 55.

The spelling of 25661722316617 in words is "twenty-five trillion, six hundred sixty-one billion, seven hundred twenty-two million, three hundred sixteen thousand, six hundred seventeen".