28646689 has 4 divisors (see below), whose sum is σ = 28805140. Its totient is φ = 28488240.

The previous prime is 28646677. The next prime is 28646711. The reversal of 28646689 is 98664682.

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 4558225 + 24088464 = 2135^2 + 4908^2 .

It is a cyclic number.

It is not a de Polignac number, because 28646689 - 2⁷ = 28646561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28646609) 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, 78954 + ... + 79315.

It is an arithmetic number, because the mean of its divisors is an integer number (7201285).

Almost surely, 2^28646689 is an apocalyptic number.

It is an amenable number.

28646689 is a deficient number, since it is larger than the sum of its proper divisors (158451).

28646689 is a wasteful number, since it uses less digits than its factorization.

28646689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158450.

The product of its digits is 995328, while the sum is 49.

The square root of 28646689 is about 5352.2601767851. The cubic root of 28646689 is about 305.9788991103.

The spelling of 28646689 in words is "twenty-eight million, six hundred forty-six thousand, six hundred eighty-nine".