28178993 has 2 divisors, whose sum is σ = 28178994. Its totient is φ = 28178992.

The previous prime is 28178989. The next prime is 28178999. The reversal of 28178993 is 39987182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27164944 + 1014049 = 5212^2 + 1007^2 .

It is a cyclic number.

It is not a de Polignac number, because 28178993 - 2² = 28178989 is a prime.

It is not a weakly prime, because it can be changed into another prime (28178999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14089496 + 14089497.

It is an arithmetic number, because the mean of its divisors is an integer number (14089497).

Almost surely, 2^28178993 is an apocalyptic number.

It is an amenable number.

28178993 is a deficient number, since it is larger than the sum of its proper divisors (1).

28178993 is an equidigital number, since it uses as much as digits as its factorization.

28178993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 47.

The square root of 28178993 is about 5308.3889269721. The cubic root of 28178993 is about 304.3045806141.

The spelling of 28178993 in words is "twenty-eight million, one hundred seventy-eight thousand, nine hundred ninety-three".