25666531663 has 4 divisors (see below), whose sum is σ = 25667976600. Its totient is φ = 25665086728.

The previous prime is 25666531637. The next prime is 25666531687. The reversal of 25666531663 is 36613566652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 25666531663 - 2¹³ = 25666523471 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25666535663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 695488 + ... + 731461.

It is an arithmetic number, because the mean of its divisors is an integer number (6416994150).

Almost surely, 2^25666531663 is an apocalyptic number.

25666531663 is a deficient number, since it is larger than the sum of its proper divisors (1444937).

25666531663 is a wasteful number, since it uses less digits than its factorization.

25666531663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1444936.

The product of its digits is 3499200, while the sum is 49.

The spelling of 25666531663 in words is "twenty-five billion, six hundred sixty-six million, five hundred thirty-one thousand, six hundred sixty-three".