28109540281 has 9 divisors (see below), whose sum is σ = 28247526223. Its totient is φ = 27972227560.

The previous prime is 28109540279. The next prime is 28109540293. The reversal of 28109540281 is 18204590182.

The square root of 28109540281 is 167659.

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., 6635568681 + 21473971600 = 81459^2 + 146540^2 .

It is not a de Polignac number, because 28109540281 - 2¹ = 28109540279 is a prime.

It is a super-2 number, since 2×28109540281² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28109540201) 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, 65219136 + ... + 65219566.

Almost surely, 2^28109540281 is an apocalyptic number.

28109540281 is the 167659-th square number.

28109540281 is the 83830-th centered octagonal number.

It is an amenable number.

28109540281 is a deficient number, since it is larger than the sum of its proper divisors (137985942).

28109540281 is an frugal number, since it uses more digits than its factorization.

28109540281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1640 (or 820 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 40.

The spelling of 28109540281 in words is "twenty-eight billion, one hundred nine million, five hundred forty thousand, two hundred eighty-one".