205309495091 has 8 divisors (see below), whose sum is σ = 217427783184. Its totient is φ = 193195791360.

The previous prime is 205309495037. The next prime is 205309495099. The reversal of 205309495091 is 190594903502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205309495091 - 2³⁴ = 188129625907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205309495099) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1053665 + ... + 1233218.

It is an arithmetic number, because the mean of its divisors is an integer number (27178472898).

Almost surely, 2^205309495091 is an apocalyptic number.

205309495091 is a deficient number, since it is larger than the sum of its proper divisors (12118288093).

205309495091 is a wasteful number, since it uses less digits than its factorization.

205309495091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2292181.

The product of its (nonzero) digits is 437400, while the sum is 47.

The spelling of 205309495091 in words is "two hundred five billion, three hundred nine million, four hundred ninety-five thousand, ninety-one".