28930267921 has 9 divisors (see below), whose sum is σ = 29739768849. Its totient is φ = 28142245584.

The previous prime is 28930267867. The next prime is 28930267937. The reversal of 28930267921 is 12976203982.

The square root of 28930267921 is 170089.

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

It can be written as a sum of positive squares in 4 ways, for example, as 98227921 + 28832040000 = 9911^2 + 169800^2 .

It is not a de Polignac number, because 28930267921 - 2²³ = 28921879313 is a prime.

It is a super-3 number, since 3×28930267921³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28930267991) 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 8 ways as a sum of consecutive naturals, for example, 6290995 + ... + 6295591.

It is an arithmetic number, because the mean of its divisors is an integer number (3304418761).

Almost surely, 2^28930267921 is an apocalyptic number.

28930267921 is the 170089-th square number.

28930267921 is the 85045-th centered octagonal number.

It is an amenable number.

28930267921 is a deficient number, since it is larger than the sum of its proper divisors (809500928).

28930267921 is an frugal number, since it uses more digits than its factorization.

28930267921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9268 (or 4634 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 49.

Multiplying 28930267921 by its sum of digits (49), we get a square (1417583128129 = 1190623²).

The spelling of 28930267921 in words is "twenty-eight billion, nine hundred thirty million, two hundred sixty-seven thousand, nine hundred twenty-one".