28317821841 has 9 divisors (see below), whose sum is σ = 40904249659. Its totient is φ = 18878211336.

The previous prime is 28317821803. The next prime is 28317821867. The reversal of 28317821841 is 14812871382.

The square root of 28317821841 is 168279.

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., 6237050625 + 22080771216 = 78975^2 + 148596^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-28317821841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28317821341) 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, 476791 + ... + 532883.

Almost surely, 2^28317821841 is an apocalyptic number.

28317821841 is the 168279-th square number.

28317821841 is the 84140-th centered octagonal number.

It is an amenable number.

28317821841 is a deficient number, since it is larger than the sum of its proper divisors (12586427818).

28317821841 is an frugal number, since it uses more digits than its factorization.

28317821841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112192 (or 56096 counting only the distinct ones).

The product of its digits is 172032, while the sum is 45.

The spelling of 28317821841 in words is "twenty-eight billion, three hundred seventeen million, eight hundred twenty-one thousand, eight hundred forty-one".