28107691 has 4 divisors (see below), whose sum is σ = 28126312. Its totient is φ = 28089072.

The previous prime is 28107683. The next prime is 28107697. The reversal of 28107691 is 19670182.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 28107691 - 2³ = 28107683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28107697) 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, 6825 + ... + 10138.

It is an arithmetic number, because the mean of its divisors is an integer number (7031578).

Almost surely, 2^28107691 is an apocalyptic number.

28107691 is a deficient number, since it is larger than the sum of its proper divisors (18621).

28107691 is a wasteful number, since it uses less digits than its factorization.

28107691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18620.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 28107691 is about 5301.6686995700. The cubic root of 28107691 is about 304.0477007039.

It can be divided in two parts, 2810 and 7691, that added together give a palindrome (10501).

The spelling of 28107691 in words is "twenty-eight million, one hundred seven thousand, six hundred ninety-one".