28193432281 has 45 divisors (see below), whose sum is σ = 35271086601. Its totient is φ = 22470254016.

The previous prime is 28193432257. The next prime is 28193432291. The reversal of 28193432281 is 18223439182.

The square root of 28193432281 is 167909.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8749918681 + 19443513600 = 93541^2 + 139440^2 .

It is not a de Polignac number, because 28193432281 - 2²³ = 28185043673 is a prime.

It is a super-2 number, since 2×28193432281² (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 (28193432291) 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 44 ways as a sum of consecutive naturals, for example, 339679866 + ... + 339679948.

Almost surely, 2^28193432281 is an apocalyptic number.

28193432281 is the 167909-th square number.

28193432281 is the 83955-th centered octagonal number.

It is an amenable number.

28193432281 is a deficient number, since it is larger than the sum of its proper divisors (7077654320).

28193432281 is an frugal number, since it uses more digits than its factorization.

28193432281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248 (or 107 counting only the distinct ones).

The product of its digits is 165888, while the sum is 43.

The spelling of 28193432281 in words is "twenty-eight billion, one hundred ninety-three million, four hundred thirty-two thousand, two hundred eighty-one".