28277561 has 4 divisors (see below), whose sum is σ = 30452772. Its totient is φ = 26102352.

The previous prime is 28277533. The next prime is 28277563. The reversal of 28277561 is 16577282.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7529536 + 20748025 = 2744^2 + 4555^2 .

It is a cyclic number.

It is not a de Polignac number, because 28277561 - 2¹⁸ = 28015417 is a prime.

It is a super-2 number, since 2×28277561² = 1599240912217442, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28277563) 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, 1087586 + ... + 1087611.

It is an arithmetic number, because the mean of its divisors is an integer number (7613193).

Almost surely, 2^28277561 is an apocalyptic number.

It is an amenable number.

28277561 is a deficient number, since it is larger than the sum of its proper divisors (2175211).

28277561 is a wasteful number, since it uses less digits than its factorization.

28277561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2175210.

The product of its digits is 47040, while the sum is 38.

The square root of 28277561 is about 5317.6649950895. The cubic root of 28277561 is about 304.6589792335.

The spelling of 28277561 in words is "twenty-eight million, two hundred seventy-seven thousand, five hundred sixty-one".