21788093 has 2 divisors, whose sum is σ = 21788094. Its totient is φ = 21788092.

The previous prime is 21788083. The next prime is 21788099. The reversal of 21788093 is 39088712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20593444 + 1194649 = 4538^2 + 1093^2 .

It is a cyclic number.

It is not a de Polignac number, because 21788093 - 2⁶ = 21788029 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21788099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10894046 + 10894047.

It is an arithmetic number, because the mean of its divisors is an integer number (10894047).

Almost surely, 2^21788093 is an apocalyptic number.

It is an amenable number.

21788093 is a deficient number, since it is larger than the sum of its proper divisors (1).

21788093 is an equidigital number, since it uses as much as digits as its factorization.

21788093 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 21788093 is about 4667.7717382066. The cubic root of 21788093 is about 279.3013748137.

The spelling of 21788093 in words is "twenty-one million, seven hundred eighty-eight thousand, ninety-three".