28109986 has 4 divisors (see below), whose sum is σ = 42164982. Its totient is φ = 14054992.

The previous prime is 28109971. The next prime is 28109989. The reversal of 28109986 is 68990182.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 15642025 + 12467961 = 3955^2 + 3531^2 .

It is not an unprimeable number, because it can be changed into a prime (28109989) 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 as a sum of consecutive naturals, namely, 7027495 + ... + 7027498.

Almost surely, 2^28109986 is an apocalyptic number.

28109986 is a deficient number, since it is larger than the sum of its proper divisors (14054996).

28109986 is a wasteful number, since it uses less digits than its factorization.

28109986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14054995.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 28109986 is about 5301.8851364397. The cubic root of 28109986 is about 304.0559756690.

The spelling of 28109986 in words is "twenty-eight million, one hundred nine thousand, nine hundred eighty-six".