209869353225 has 81 divisors (see below), whose sum is σ = 437370895143. Its totient is φ = 95918286240.

The previous prime is 209869353191. The next prime is 209869353251. The reversal of 209869353225 is 522353968902.

The square root of 209869353225 is 458115.

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

209869353225 is a `hidden beast` number, since 2 + 0 + 9 + 8 + 69 + 353 + 225 = 666.

It can be written as a sum of positive squares in only one way, i.e., 75552967161 + 134316386064 = 274869^2 + 366492^2 .

It is not a de Polignac number, because 209869353225 - 2¹⁹ = 209868828937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 48099894 + ... + 48104256.

Almost surely, 2^209869353225 is an apocalyptic number.

209869353225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

209869353225 is the 458115-th square number.

209869353225 is the 229058-th centered octagonal number.

It is an amenable number.

209869353225 is an abundant number, since it is smaller than the sum of its proper divisors (227501541918).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209869353225 is an frugal number, since it uses more digits than its factorization.

209869353225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8756 (or 4378 counting only the distinct ones).

The product of its (nonzero) digits is 6998400, while the sum is 54.

The spelling of 209869353225 in words is "two hundred nine billion, eight hundred sixty-nine million, three hundred fifty-three thousand, two hundred twenty-five".