21108793 has 2 divisors, whose sum is σ = 21108794. Its totient is φ = 21108792.

The previous prime is 21108757. The next prime is 21108811. The reversal of 21108793 is 39780112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21049744 + 59049 = 4588^2 + 243^2 .

It is a cyclic number.

It is not a de Polignac number, because 21108793 - 2¹³ = 21100601 is a prime.

It is a super-2 number, since 2×21108793² = 891162283833698, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21178793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10554396 + 10554397.

It is an arithmetic number, because the mean of its divisors is an integer number (10554397).

Almost surely, 2^21108793 is an apocalyptic number.

It is an amenable number.

21108793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21108793 is an equidigital number, since it uses as much as digits as its factorization.

21108793 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21108793 is about 4594.4306502547. The cubic root of 21108793 is about 276.3680284331.

The spelling of 21108793 in words is "twenty-one million, one hundred eight thousand, seven hundred ninety-three".