205180981 has 4 divisors (see below), whose sum is σ = 215980000. Its totient is φ = 194381964.

The previous prime is 205180979. The next prime is 205181029. The reversal of 205180981 is 189081502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205180981 - 2¹ = 205180979 is a prime.

It is a super-2 number, since 2×205180981² = 84198469928244722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205180931) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5399481 + ... + 5399518.

It is an arithmetic number, because the mean of its divisors is an integer number (53995000).

Almost surely, 2^205180981 is an apocalyptic number.

It is an amenable number.

205180981 is a deficient number, since it is larger than the sum of its proper divisors (10799019).

205180981 is a wasteful number, since it uses less digits than its factorization.

205180981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10799018.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 205180981 is about 14324.1397996529. The cubic root of 205180981 is about 589.8103201427.

The spelling of 205180981 in words is "two hundred five million, one hundred eighty thousand, nine hundred eighty-one".