661005100180 has 12 divisors (see below), whose sum is σ = 1388110710420. Its totient is φ = 264402040064.

The previous prime is 661005100157. The next prime is 661005100183. The reversal of 661005100180 is 81001500166.

It can be written as a sum of positive squares in 2 ways, for example, as 170035821316 + 490969278864 = 412354^2 + 700692^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661005100183) 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, 16525127485 + ... + 16525127524.

It is an arithmetic number, because the mean of its divisors is an integer number (115675892535).

Almost surely, 2^661005100180 is an apocalyptic number.

It is an amenable number.

661005100180 is an abundant number, since it is smaller than the sum of its proper divisors (727105610240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661005100180 is a wasteful number, since it uses less digits than its factorization.

661005100180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33050255018 (or 33050255016 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The spelling of 661005100180 in words is "six hundred sixty-one billion, five million, one hundred thousand, one hundred eighty".