205309440 has 480 divisors, whose sum is σ = 868158720. Its totient is φ = 43794432.

The previous prime is 205309409. The next prime is 205309441. The reversal of 205309440 is 44903502.

205309440 is a `hidden beast` number, since 2 + 0 + 530 + 94 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a super-2 number, since 2×205309440² = 84303932306227200, which contains 22 as substring.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205309441) 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, 3064287 + ... + 3064353.

It is an arithmetic number, because the mean of its divisors is an integer number (1808664).

Almost surely, 2^205309440 is an apocalyptic number.

205309440 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 205309440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (434079360).

205309440 is an abundant number, since it is smaller than the sum of its proper divisors (662849280).

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

205309440 is a wasteful number, since it uses less digits than its factorization.

205309440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 205309440 is about 14328.6231020290. The cubic root of 205309440 is about 589.9333832667.

The spelling of 205309440 in words is "two hundred five million, three hundred nine thousand, four hundred forty".