209152561 has 4 divisors (see below), whose sum is σ = 209535472. Its totient is φ = 208769652.

The previous prime is 209152549. The next prime is 209152577. The reversal of 209152561 is 165251902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 209152561 - 2⁵ = 209152529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209152061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190635 + ... + 191728.

It is an arithmetic number, because the mean of its divisors is an integer number (52383868).

Almost surely, 2^209152561 is an apocalyptic number.

It is an amenable number.

209152561 is a deficient number, since it is larger than the sum of its proper divisors (382911).

209152561 is an equidigital number, since it uses as much as digits as its factorization.

209152561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382910.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 209152561 is about 14462.1077647762. The cubic root of 209152561 is about 593.5915758901.

The spelling of 209152561 in words is "two hundred nine million, one hundred fifty-two thousand, five hundred sixty-one".