205745440 has 48 divisors (see below), whose sum is σ = 488949048. Its totient is φ = 81811456.

The previous prime is 205745431. The next prime is 205745447. The reversal of 205745440 is 44547502.

It can be written as a sum of positive squares in 4 ways, for example, as 159668496 + 46076944 = 12636^2 + 6788^2 .

It is not an unprimeable number, because it can be changed into a prime (205745447) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 23964 + ... + 31396.

Almost surely, 2^205745440 is an apocalyptic number.

205745440 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 205745440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244474524).

205745440 is an abundant number, since it is smaller than the sum of its proper divisors (283203608).

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

205745440 is a wasteful number, since it uses less digits than its factorization.

205745440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7621 (or 7613 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 31.

The square root of 205745440 is about 14343.8293352926. The cubic root of 205745440 is about 590.3506868525.

The spelling of 205745440 in words is "two hundred five million, seven hundred forty-five thousand, four hundred forty".