28249861 has 4 divisors (see below), whose sum is σ = 28938924. Its totient is φ = 27560800.

The previous prime is 28249843. The next prime is 28249877. The reversal of 28249861 is 16894282.

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 16859236 + 11390625 = 4106^2 + 3375^2 .

It is a cyclic number.

It is not a de Polignac number, because 28249861 - 2¹⁷ = 28118789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28249831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344470 + ... + 344551.

It is an arithmetic number, because the mean of its divisors is an integer number (7234731).

Almost surely, 2^28249861 is an apocalyptic number.

It is an amenable number.

28249861 is a deficient number, since it is larger than the sum of its proper divisors (689063).

28249861 is an equidigital number, since it uses as much as digits as its factorization.

28249861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689062.

The product of its digits is 55296, while the sum is 40.

The square root of 28249861 is about 5315.0598303312. The cubic root of 28249861 is about 304.5594679309.

The spelling of 28249861 in words is "twenty-eight million, two hundred forty-nine thousand, eight hundred sixty-one".