28861691 has 4 divisors (see below), whose sum is σ = 28947672. Its totient is φ = 28775712.

The previous prime is 28861667. The next prime is 28861697. The reversal of 28861691 is 19616882.

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 28861691 - 2¹⁴ = 28845307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28861697) 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, 42485 + ... + 43158.

It is an arithmetic number, because the mean of its divisors is an integer number (7236918).

Almost surely, 2^28861691 is an apocalyptic number.

28861691 is a deficient number, since it is larger than the sum of its proper divisors (85981).

28861691 is an equidigital number, since it uses as much as digits as its factorization.

28861691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85980.

The product of its digits is 41472, while the sum is 41.

The square root of 28861691 is about 5372.3077908847. The cubic root of 28861691 is about 306.7424798121.

The spelling of 28861691 in words is "twenty-eight million, eight hundred sixty-one thousand, six hundred ninety-one".