186561521728 has 14 divisors (see below), whose sum is σ = 370208019806. Its totient is φ = 93280760832.

The previous prime is 186561521723. The next prime is 186561521749. The reversal of 186561521728 is 827125165681.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 136184617024 + 50376904704 = 369032^2 + 224448^2 .

It is a super-2 number, since 2×186561521728² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (186561521723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1457511825 + ... + 1457511952.

Almost surely, 2^186561521728 is an apocalyptic number.

It is an amenable number.

186561521728 is a deficient number, since it is larger than the sum of its proper divisors (183646498078).

186561521728 is an equidigital number, since it uses as much as digits as its factorization.

186561521728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2915023789 (or 2915023779 counting only the distinct ones).

The product of its digits is 1612800, while the sum is 52.

The spelling of 186561521728 in words is "one hundred eighty-six billion, five hundred sixty-one million, five hundred twenty-one thousand, seven hundred twenty-eight".