209852865 has 24 divisors (see below), whose sum is σ = 366972840. Its totient is φ = 110928384.

The previous prime is 209852849. The next prime is 209852869. The reversal of 209852865 is 568258902.

It can be written as a sum of positive squares in 4 ways, for example, as 24920064 + 184932801 = 4992^2 + 13599^2 .

It is not a de Polignac number, because 209852865 - 2⁴ = 209852849 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 209852865.

It is not an unprimeable number, because it can be changed into a prime (209852869) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15550 + ... + 25719.

It is an arithmetic number, because the mean of its divisors is an integer number (15290535).

Almost surely, 2^209852865 is an apocalyptic number.

It is an amenable number.

209852865 is a deficient number, since it is larger than the sum of its proper divisors (157119975).

209852865 is a wasteful number, since it uses less digits than its factorization.

209852865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41393 (or 41390 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The square root of 209852865 is about 14486.2992168462. The cubic root of 209852865 is about 594.2533439609.

The spelling of 209852865 in words is "two hundred nine million, eight hundred fifty-two thousand, eight hundred sixty-five".