205145640 has 192 divisors, whose sum is σ = 769167360. Its totient is φ = 46448640.

The previous prime is 205145617. The next prime is 205145653. The reversal of 205145640 is 46541502.

205145640 is a `hidden beast` number, since 2 + 0 + 5 + 14 + 5 + 640 = 666.

It is a super-2 number, since 2×205145640² = 84169467222019200, which contains 22 as substring.

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 319720 + ... + 320360.

It is an arithmetic number, because the mean of its divisors is an integer number (4006080).

Almost surely, 2^205145640 is an apocalyptic number.

205145640 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 205145640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (384583680).

205145640 is an abundant number, since it is smaller than the sum of its proper divisors (564021720).

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

205145640 is a wasteful number, since it uses less digits than its factorization.

205145640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792 (or 785 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 205145640 is about 14322.9061296931. The cubic root of 205145640 is about 589.7764546201.

The spelling of 205145640 in words is "two hundred five million, one hundred forty-five thousand, six hundred forty".