205221640 has 64 divisors (see below), whose sum is σ = 518918400. Its totient is φ = 72475392.

The previous prime is 205221631. The next prime is 205221677. The reversal of 205221640 is 46122502.

205221640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3381 + ... + 20539.

It is an arithmetic number, because the mean of its divisors is an integer number (8108100).

Almost surely, 2^205221640 is an apocalyptic number.

205221640 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 205221640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (259459200).

205221640 is an abundant number, since it is smaller than the sum of its proper divisors (313696760).

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

205221640 is a wasteful number, since it uses less digits than its factorization.

205221640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17206 (or 17202 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 205221640 is about 14325.5589768777. The cubic root of 205221640 is about 589.8492768299.

The spelling of 205221640 in words is "two hundred five million, two hundred twenty-one thousand, six hundred forty".