28666139 has 4 divisors (see below), whose sum is σ = 28676856. Its totient is φ = 28655424.

The previous prime is 28666133. The next prime is 28666147. The reversal of 28666139 is 93166682.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28666139 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28666096 and 28666105.

It is not an unprimeable number, because it can be changed into a prime (28666133) 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, 2372 + ... + 7934.

It is an arithmetic number, because the mean of its divisors is an integer number (7169214).

Almost surely, 2^28666139 is an apocalyptic number.

28666139 is a deficient number, since it is larger than the sum of its proper divisors (10717).

28666139 is an equidigital number, since it uses as much as digits as its factorization.

28666139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10716.

The product of its digits is 93312, while the sum is 41.

The square root of 28666139 is about 5354.0768578720. The cubic root of 28666139 is about 306.0481327449.

The spelling of 28666139 in words is "twenty-eight million, six hundred sixty-six thousand, one hundred thirty-nine".