205213640 has 32 divisors (see below), whose sum is σ = 463510080. Its totient is φ = 81769152.

The previous prime is 205213627. The next prime is 205213663. The reversal of 205213640 is 46312502.

It is a super-2 number, since 2×205213640² = 84225276084099200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 767 + ... + 20273.

It is an arithmetic number, because the mean of its divisors is an integer number (14484690).

Almost surely, 2^205213640 is an apocalyptic number.

205213640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205213640 is an abundant number, since it is smaller than the sum of its proper divisors (258296440).

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

205213640 is a wasteful number, since it uses less digits than its factorization.

205213640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19781 (or 19777 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 205213640 is about 14325.2797529403. The cubic root of 205213640 is about 589.8416121809.

The spelling of 205213640 in words is "two hundred five million, two hundred thirteen thousand, six hundred forty".