209689693 has 8 divisors (see below), whose sum is σ = 217267128. Its totient is φ = 202212864.

The previous prime is 209689687. The next prime is 209689721. The reversal of 209689693 is 396986902.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 19166884 + 190522809 = 4378^2 + 13803^2 .

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 209689693 - 2²⁵ = 176135261 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 209689693.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209689603) 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, 20896 + ... + 29257.

It is an arithmetic number, because the mean of its divisors is an integer number (27158391).

Almost surely, 2^209689693 is an apocalyptic number.

It is an amenable number.

209689693 is a deficient number, since it is larger than the sum of its proper divisors (7577435).

209689693 is a wasteful number, since it uses less digits than its factorization.

209689693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50303.

The product of its (nonzero) digits is 1259712, while the sum is 52.

The square root of 209689693 is about 14480.6661794270. Note that the first 3 decimals coincide. The cubic root of 209689693 is about 594.0992826070.

The spelling of 209689693 in words is "two hundred nine million, six hundred eighty-nine thousand, six hundred ninety-three".