25505048209 has 9 divisors (see below), whose sum is σ = 26419657147. Its totient is φ = 24621092104.

The previous prime is 25505048207. The next prime is 25505048249. The reversal of 25505048209 is 90284050552.

The square root of 25505048209 is 159703.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 13374228609 + 12130819600 = 115647^2 + 110140^2 .

It is not a de Polignac number, because 25505048209 - 2¹ = 25505048207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25505048203) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4628634 + ... + 4634140.

Almost surely, 2^25505048209 is an apocalyptic number.

25505048209 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

25505048209 is the 159703-rd square number.

25505048209 is the 79852-nd centered octagonal number.

It is an amenable number.

25505048209 is a deficient number, since it is larger than the sum of its proper divisors (914608938).

25505048209 is an frugal number, since it uses more digits than its factorization.

25505048209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11072 (or 5536 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 40.

The spelling of 25505048209 in words is "twenty-five billion, five hundred five million, forty-eight thousand, two hundred nine".