209159961 has 8 divisors (see below), whose sum is σ = 293557920. Its totient is φ = 132100992.

The previous prime is 209159947. The next prime is 209159981. The reversal of 209159961 is 169951902.

It is a happy number.

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

It is not a de Polignac number, because 209159961 - 2¹³ = 209151769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (209159981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1834680 + ... + 1834793.

It is an arithmetic number, because the mean of its divisors is an integer number (36694740).

Almost surely, 2^209159961 is an apocalyptic number.

It is an amenable number.

209159961 is a deficient number, since it is larger than the sum of its proper divisors (84397959).

209159961 is a wasteful number, since it uses less digits than its factorization.

209159961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3669495.

The product of its (nonzero) digits is 43740, while the sum is 42.

The square root of 209159961 is about 14462.3636035055. The cubic root of 209159961 is about 593.5985764034.

It can be divided in two parts, 20915 and 9961, that added together give a triangular number (30876 = T₂₄₈).

The spelling of 209159961 in words is "two hundred nine million, one hundred fifty-nine thousand, nine hundred sixty-one".