205400811 has 64 divisors (see below), whose sum is σ = 366612480. Its totient is φ = 99066240.

The previous prime is 205400779. The next prime is 205400813. The reversal of 205400811 is 118004502.

It is not a de Polignac number, because 205400811 - 2⁵ = 205400779 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (205400813) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 232176 + ... + 233058.

It is an arithmetic number, because the mean of its divisors is an integer number (5728320).

Almost surely, 2^205400811 is an apocalyptic number.

205400811 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

205400811 is a deficient number, since it is larger than the sum of its proper divisors (161211669).

205400811 is a wasteful number, since it uses less digits than its factorization.

205400811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 976.

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 205400811 is about 14331.8111556077. The cubic root of 205400811 is about 590.0208850215.

The spelling of 205400811 in words is "two hundred five million, four hundred thousand, eight hundred eleven".