205317990 has 96 divisors (see below), whose sum is σ = 582865920. Its totient is φ = 51858144.

The previous prime is 205317947. The next prime is 205317997. The reversal of 205317990 is 99713502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205317997) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 43947 + ... + 48393.

It is an arithmetic number, because the mean of its divisors is an integer number (6071520).

Almost surely, 2^205317990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205317990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291432960).

205317990 is an abundant number, since it is smaller than the sum of its proper divisors (377547930).

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

205317990 is a wasteful number, since it uses less digits than its factorization.

205317990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4488 (or 4476 counting only the distinct ones).

The product of its (nonzero) digits is 17010, while the sum is 36.

The square root of 205317990 is about 14328.9214527821. The cubic root of 205317990 is about 589.9415723047.

The spelling of 205317990 in words is "two hundred five million, three hundred seventeen thousand, nine hundred ninety".