25535081209 has 27 divisors (see below), whose sum is σ = 28600958799. Its totient is φ = 22780660320.

The previous prime is 25535081191. The next prime is 25535081213. The reversal of 25535081209 is 90218053552.

The square root of 25535081209 is 159797.

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., 14494956025 + 11040125184 = 120395^2 + 105072^2 .

It is not a de Polignac number, because 25535081209 - 2¹³ = 25535073017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25535081809) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 128316892 + ... + 128317090.

Almost surely, 2^25535081209 is an apocalyptic number.

25535081209 is the 159797-th square number.

25535081209 is the 79899-th centered octagonal number.

It is an amenable number.

25535081209 is a deficient number, since it is larger than the sum of its proper divisors (3065877590).

25535081209 is an frugal number, since it uses more digits than its factorization.

25535081209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 25535081209 in words is "twenty-five billion, five hundred thirty-five million, eighty-one thousand, two hundred nine".