209661340 has 48 divisors (see below), whose sum is σ = 532792512. Its totient is φ = 67654656.

The previous prime is 209661317. The next prime is 209661343. The reversal of 209661340 is 43166902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209661343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41667 + ... + 46426.

It is an arithmetic number, because the mean of its divisors is an integer number (11099844).

Almost surely, 2^209661340 is an apocalyptic number.

209661340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

209661340 is an abundant number, since it is smaller than the sum of its proper divisors (323131172).

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

209661340 is a wasteful number, since it uses less digits than its factorization.

209661340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88126 (or 88124 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 209661340 is about 14479.6871513165. The cubic root of 209661340 is about 594.0725045364.

It can be divided in two parts, 2096 and 61340, that added together give a palindrome (63436).

The spelling of 209661340 in words is "two hundred nine million, six hundred sixty-one thousand, three hundred forty".