28530925921 has 9 divisors (see below), whose sum is σ = 29088529491. Its totient is φ = 27983823192.

The previous prime is 28530925883. The next prime is 28530925933. The reversal of 28530925921 is 12952903582.

The square root of 28530925921 is 168911.

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., 20567862225 + 7963063696 = 143415^2 + 89236^2 .

It is not a de Polignac number, because 28530925921 - 2¹⁹ = 28530401633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28530925961) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 8950690 + ... + 8953876.

Almost surely, 2^28530925921 is an apocalyptic number.

28530925921 is the 168911-st square number.

28530925921 is the 84456-th centered octagonal number.

It is an amenable number.

28530925921 is a deficient number, since it is larger than the sum of its proper divisors (557603570).

28530925921 is an frugal number, since it uses more digits than its factorization.

28530925921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6480 (or 3240 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 46.

The spelling of 28530925921 in words is "twenty-eight billion, five hundred thirty million, nine hundred twenty-five thousand, nine hundred twenty-one".