5661810731988 has 72 divisors (see below), whose sum is σ = 14508695591208. Its totient is φ = 1861438722048.

The previous prime is 5661810731981. The next prime is 5661810732007. The reversal of 5661810731988 is 8891370181665.

5661810731988 is a `hidden beast` number, since 5 + 6 + 618 + 1 + 0 + 7 + 3 + 1 + 9 + 8 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2716701690564 + 2945109041424 = 1648242^2 + 1716132^2 .

It is a super-2 number, since 2×5661810731988² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5661810731981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1743681 + ... + 3789992.

It is an arithmetic number, because the mean of its divisors is an integer number (201509660989).

Almost surely, 2^{5661810731988} is an apocalyptic number.

It is an amenable number.

5661810731988 is an abundant number, since it is smaller than the sum of its proper divisors (8846884859220).

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

5661810731988 is a wasteful number, since it uses less digits than its factorization.

5661810731988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5534073 (or 5534068 counting only the distinct ones).

The product of its (nonzero) digits is 17418240, while the sum is 63.

The spelling of 5661810731988 in words is "five trillion, six hundred sixty-one billion, eight hundred ten million, seven hundred thirty-one thousand, nine hundred eighty-eight".