28218791 has 2 divisors, whose sum is σ = 28218792. Its totient is φ = 28218790.

The previous prime is 28218787. The next prime is 28218809. The reversal of 28218791 is 19781282.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28218791 - 2² = 28218787 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28218731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14109395 + 14109396.

It is an arithmetic number, because the mean of its divisors is an integer number (14109396).

Almost surely, 2^28218791 is an apocalyptic number.

28218791 is a deficient number, since it is larger than the sum of its proper divisors (1).

28218791 is an equidigital number, since it uses as much as digits as its factorization.

28218791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 38.

The square root of 28218791 is about 5312.1361993081. The cubic root of 28218791 is about 304.4477725861.

The spelling of 28218791 in words is "twenty-eight million, two hundred eighteen thousand, seven hundred ninety-one".