205898640 has 80 divisors (see below), whose sum is σ = 650369088. Its totient is φ = 53867008.

The previous prime is 205898639. The next prime is 205898657. The reversal of 205898640 is 46898502.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 205898592 and 205898601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4627 + ... + 20813.

Almost surely, 2^205898640 is an apocalyptic number.

205898640 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 205898640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (325184544).

205898640 is an abundant number, since it is smaller than the sum of its proper divisors (444470448).

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

205898640 is a wasteful number, since it uses less digits than its factorization.

205898640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16256 (or 16250 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The square root of 205898640 is about 14349.1686170314. The cubic root of 205898640 is about 590.4971774002.

The spelling of 205898640 in words is "two hundred five million, eight hundred ninety-eight thousand, six hundred forty".