205611531645 has 16 divisors (see below), whose sum is σ = 354284485632. Its totient is φ = 101224138560.

The previous prime is 205611531617. The next prime is 205611531649. The reversal of 205611531645 is 546135116502.

It is not a de Polignac number, because 205611531645 - 2⁵ = 205611531613 is a prime.

It is a super-2 number, since 2×205611531645² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205611531649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 527208861 + ... + 527209250.

It is an arithmetic number, because the mean of its divisors is an integer number (22142780352).

Almost surely, 2^205611531645 is an apocalyptic number.

It is an amenable number.

205611531645 is a deficient number, since it is larger than the sum of its proper divisors (148672953987).

205611531645 is a wasteful number, since it uses less digits than its factorization.

205611531645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054418132.

The product of its (nonzero) digits is 108000, while the sum is 39.

The spelling of 205611531645 in words is "two hundred five billion, six hundred eleven million, five hundred thirty-one thousand, six hundred forty-five".