205711091042 has 18 divisors (see below), whose sum is σ = 319602669633. Its totient is φ = 99299822664.

The previous prime is 205711091041. The next prime is 205711091093. The reversal of 205711091042 is 240190117502.

It can be written as a sum of positive squares in 2 ways, for example, as 205588789561 + 122301481 = 453419^2 + 11059^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=320711.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205711091041) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 18595709 + ... + 18606767.

Almost surely, 2^205711091042 is an apocalyptic number.

205711091042 is a deficient number, since it is larger than the sum of its proper divisors (113891578591).

205711091042 is an frugal number, since it uses more digits than its factorization.

205711091042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22178 (or 11090 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

Multiplying 205711091042 by its sum of digits (32), we get a square (6582754913344 = 2565688²).

The spelling of 205711091042 in words is "two hundred five billion, seven hundred eleven million, ninety-one thousand, forty-two".