205253640 has 96 divisors (see below), whose sum is σ = 669778200. Its totient is φ = 54512640.

The previous prime is 205253639. The next prime is 205253641. The reversal of 205253640 is 46352502.

It is an interprime number because it is at equal distance from previous prime (205253639) and next prime (205253641).

It can be written as a sum of positive squares in 4 ways, for example, as 205119684 + 133956 = 14322^2 + 366^2 .

It is not an unprimeable number, because it can be changed into a prime (205253641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 100146 + ... + 102174.

Almost surely, 2^205253640 is an apocalyptic number.

205253640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205253640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (334889100).

205253640 is an abundant number, since it is smaller than the sum of its proper divisors (464524560).

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

205253640 is a wasteful number, since it uses less digits than its factorization.

205253640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2327 (or 2320 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 27.

The square root of 205253640 is about 14326.6758182071. The cubic root of 205253640 is about 589.8799334343.

The spelling of 205253640 in words is "two hundred five million, two hundred fifty-three thousand, six hundred forty".