28140561 has 8 divisors (see below), whose sum is σ = 41689760. Its totient is φ = 18760356.

The previous prime is 28140557. The next prime is 28140571. The reversal of 28140561 is 16504182.

It is not a de Polignac number, because 28140561 - 2² = 28140557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 1042243 = 28140561 / (2 + 8 + 1 + 4 + 0 + 5 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28140521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 521095 + ... + 521148.

It is an arithmetic number, because the mean of its divisors is an integer number (5211220).

Almost surely, 2^28140561 is an apocalyptic number.

It is an amenable number.

28140561 is a deficient number, since it is larger than the sum of its proper divisors (13549199).

28140561 is a wasteful number, since it uses less digits than its factorization.

28140561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1042252 (or 1042246 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 28140561 is about 5304.7677611748. The cubic root of 28140561 is about 304.1661754501.

The spelling of 28140561 in words is "twenty-eight million, one hundred forty thousand, five hundred sixty-one".