28130786 has 4 divisors (see below), whose sum is σ = 42196182. Its totient is φ = 14065392.

The previous prime is 28130779. The next prime is 28130803. The reversal of 28130786 is 68703182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68703182 = 2 ⋅34351591.

It can be written as a sum of positive squares in only one way, i.e., 26988025 + 1142761 = 5195^2 + 1069^2 .

It is a super-2 number, since 2×28130786² = 1582682241955592, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7032695 + ... + 7032698.

Almost surely, 2^28130786 is an apocalyptic number.

28130786 is a deficient number, since it is larger than the sum of its proper divisors (14065396).

28130786 is a wasteful number, since it uses less digits than its factorization.

28130786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14065395.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 28130786 is about 5303.8463401573. The cubic root of 28130786 is about 304.1309526425.

The spelling of 28130786 in words is "twenty-eight million, one hundred thirty thousand, seven hundred eighty-six".