665661543660 has 72 divisors (see below), whose sum is σ = 2022446252736. Its totient is φ = 177222017280.

The previous prime is 665661543637. The next prime is 665661543671. The reversal of 665661543660 is 66345166566.

665661543660 is a `hidden beast` number, since 6 + 6 + 566 + 15 + 4 + 3 + 6 + 60 = 666.

665661543660 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 665661543597 and 665661543606.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2885796 + ... + 3107915.

It is an arithmetic number, because the mean of its divisors is an integer number (28089531288).

Almost surely, 2^665661543660 is an apocalyptic number.

665661543660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

665661543660 is an abundant number, since it is smaller than the sum of its proper divisors (1356784709076).

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

665661543660 is a wasteful number, since it uses less digits than its factorization.

665661543660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5994343 (or 5994338 counting only the distinct ones).

The product of its (nonzero) digits is 13996800, while the sum is 54.

The spelling of 665661543660 in words is "six hundred sixty-five billion, six hundred sixty-one million, five hundred forty-three thousand, six hundred sixty".