205556258981 has 4 divisors (see below), whose sum is σ = 205700713152. Its totient is φ = 205411804812.

The previous prime is 205556258977. The next prime is 205556259001. The reversal of 205556258981 is 189852655502.

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 205556258981 - 2² = 205556258977 is a prime.

It is a super-2 number, since 2×205556258981² (a number of 23 digits) 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 (205556255981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72224951 + ... + 72227796.

It is an arithmetic number, because the mean of its divisors is an integer number (51425178288).

Almost surely, 2^205556258981 is an apocalyptic number.

It is an amenable number.

205556258981 is a deficient number, since it is larger than the sum of its proper divisors (144454171).

205556258981 is a wasteful number, since it uses less digits than its factorization.

205556258981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144454170.

The product of its (nonzero) digits is 8640000, while the sum is 56.

The spelling of 205556258981 in words is "two hundred five billion, five hundred fifty-six million, two hundred fifty-eight thousand, nine hundred eighty-one".