25861632209 has 16 divisors (see below), whose sum is σ = 30611886720. Its totient is φ = 21402588816.

The previous prime is 25861632187. The next prime is 25861632217. The reversal of 25861632209 is 90223616852.

It is not a de Polignac number, because 25861632209 - 2²⁰ = 25860583633 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25861632209.

It is not an unprimeable number, because it can be changed into a prime (25861632509) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94982 + ... + 246464.

It is an arithmetic number, because the mean of its divisors is an integer number (1913242920).

Almost surely, 2^25861632209 is an apocalyptic number.

25861632209 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

25861632209 is a deficient number, since it is larger than the sum of its proper divisors (4750254511).

25861632209 is an frugal number, since it uses more digits than its factorization.

25861632209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151577 (or 151519 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 44.

The spelling of 25861632209 in words is "twenty-five billion, eight hundred sixty-one million, six hundred thirty-two thousand, two hundred nine".