28572281 has 4 divisors (see below), whose sum is σ = 28654500. Its totient is φ = 28490064.

The previous prime is 28572259. The next prime is 28572301. The reversal of 28572281 is 18227582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18227582 = 2 ⋅9113791.

It can be written as a sum of positive squares in 2 ways, for example, as 17147881 + 11424400 = 4141^2 + 3380^2 .

It is a cyclic number.

It is not a de Polignac number, because 28572281 - 2¹⁸ = 28310137 is a prime.

It is a super-2 number, since 2×28572281² = 1632750483085922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28572781) 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 3 ways as a sum of consecutive naturals, for example, 40586 + ... + 41283.

It is an arithmetic number, because the mean of its divisors is an integer number (7163625).

Almost surely, 2^28572281 is an apocalyptic number.

It is an amenable number.

28572281 is a deficient number, since it is larger than the sum of its proper divisors (82219).

28572281 is an equidigital number, since it uses as much as digits as its factorization.

28572281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82218.

The product of its digits is 17920, while the sum is 35.

The square root of 28572281 is about 5345.3045750453. The cubic root of 28572281 is about 305.7137489956.

The spelling of 28572281 in words is "twenty-eight million, five hundred seventy-two thousand, two hundred eighty-one".