209365729225 has 9 divisors (see below), whose sum is σ = 259616341173. Its totient is φ = 167490753120.

The previous prime is 209365729219. The next prime is 209365729259. The reversal of 209365729225 is 522927563902.

The square root of 209365729225 is 457565.

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

It can be written as a sum of positive squares in 4 ways, for example, as 86420124729 + 122945604496 = 293973^2 + 350636^2 .

It is not a de Polignac number, because 209365729225 - 2³ = 209365729217 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2242069 + ... + 2333581.

Almost surely, 2^209365729225 is an apocalyptic number.

209365729225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

209365729225 is the 457565-th square number.

209365729225 is the 228783-rd centered octagonal number.

It is an amenable number.

209365729225 is a deficient number, since it is larger than the sum of its proper divisors (50250611948).

209365729225 is an frugal number, since it uses more digits than its factorization.

209365729225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183036 (or 91518 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 52.

The spelling of 209365729225 in words is "two hundred nine billion, three hundred sixty-five million, seven hundred twenty-nine thousand, two hundred twenty-five".