28664521636 has 9 divisors (see below), whose sum is σ = 50163505441. Its totient is φ = 14332091512.

The previous prime is 28664521631. The next prime is 28664521657. The reversal of 28664521636 is 63612546682.

The square root of 28664521636 is 169306.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1354976100 + 27309545536 = 36810^2 + 165256^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28664521636.

It is not an unprimeable number, because it can be changed into a prime (28664521631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 296286 + ... + 380938.

Almost surely, 2^28664521636 is an apocalyptic number.

28664521636 is the 169306-th square number.

It is an amenable number.

28664521636 is a deficient number, since it is larger than the sum of its proper divisors (21498983805).

28664521636 is an frugal number, since it uses more digits than its factorization.

28664521636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169310 (or 84655 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 49.

Multiplying 28664521636 by its sum of digits (49), we get a square (1404561560164 = 1185142²).

The spelling of 28664521636 in words is "twenty-eight billion, six hundred sixty-four million, five hundred twenty-one thousand, six hundred thirty-six".