205391840 has 48 divisors (see below), whose sum is σ = 506344608. Its totient is φ = 78583296.

The previous prime is 205391839. The next prime is 205391867. The reversal of 205391840 is 48193502.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 205391797 and 205391806.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24227 + ... + 31586.

It is an arithmetic number, because the mean of its divisors is an integer number (10548846).

Almost surely, 2^205391840 is an apocalyptic number.

205391840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205391840 is an abundant number, since it is smaller than the sum of its proper divisors (300952768).

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

205391840 is a wasteful number, since it uses less digits than its factorization.

205391840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55851 (or 55843 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 205391840 is about 14331.4981770923. The cubic root of 205391840 is about 590.0122950612.

The spelling of 205391840 in words is "two hundred five million, three hundred ninety-one thousand, eight hundred forty".