28218761 has 2 divisors, whose sum is σ = 28218762. Its totient is φ = 28218760.

The previous prime is 28218739. The next prime is 28218763. The reversal of 28218761 is 16781282.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14969161 + 13249600 = 3869^2 + 3640^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28218761 is a prime.

Together with 28218763, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28218763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14109380 + 14109381.

It is an arithmetic number, because the mean of its divisors is an integer number (14109381).

Almost surely, 2^28218761 is an apocalyptic number.

It is an amenable number.

28218761 is a deficient number, since it is larger than the sum of its proper divisors (1).

28218761 is an equidigital number, since it uses as much as digits as its factorization.

28218761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 35.

The square root of 28218761 is about 5312.1333755846. The cubic root of 28218761 is about 304.4476646978.

The spelling of 28218761 in words is "twenty-eight million, two hundred eighteen thousand, seven hundred sixty-one".