28861689 has 4 divisors (see below), whose sum is σ = 38482256. Its totient is φ = 19241124.

The previous prime is 28861667. The next prime is 28861697. The reversal of 28861689 is 98616882.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28861689 - 2¹² = 28857593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28861289) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4810279 + ... + 4810284.

It is an arithmetic number, because the mean of its divisors is an integer number (9620564).

Almost surely, 2^28861689 is an apocalyptic number.

It is an amenable number.

28861689 is a deficient number, since it is larger than the sum of its proper divisors (9620567).

28861689 is an equidigital number, since it uses as much as digits as its factorization.

28861689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9620566.

The product of its digits is 331776, while the sum is 48.

The square root of 28861689 is about 5372.3076047449. The cubic root of 28861689 is about 306.7424727268.

The spelling of 28861689 in words is "twenty-eight million, eight hundred sixty-one thousand, six hundred eighty-nine".