209969561 has 8 divisors (see below), whose sum is σ = 215826624. Its totient is φ = 204122160.

The previous prime is 209969537. The next prime is 209969579. The reversal of 209969561 is 165969902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 209969561 - 2⁶ = 209969497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (209999561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77516 + ... + 80178.

It is an arithmetic number, because the mean of its divisors is an integer number (26978328).

Almost surely, 2^209969561 is an apocalyptic number.

It is an amenable number.

209969561 is a deficient number, since it is larger than the sum of its proper divisors (5857063).

209969561 is a wasteful number, since it uses less digits than its factorization.

209969561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4831.

The product of its (nonzero) digits is 262440, while the sum is 47.

The square root of 209969561 is about 14490.3264628510. The cubic root of 209969561 is about 594.3634753108.

The spelling of 209969561 in words is "two hundred nine million, nine hundred sixty-nine thousand, five hundred sixty-one".