21307193 has 2 divisors, whose sum is σ = 21307194. Its totient is φ = 21307192.

The previous prime is 21307183. The next prime is 21307229. The reversal of 21307193 is 39170312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19465744 + 1841449 = 4412^2 + 1357^2 .

It is a cyclic number.

It is not a de Polignac number, because 21307193 - 2¹⁰ = 21306169 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21307123) 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, 10653596 + 10653597.

It is an arithmetic number, because the mean of its divisors is an integer number (10653597).

Almost surely, 2^21307193 is an apocalyptic number.

It is an amenable number.

21307193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21307193 is an equidigital number, since it uses as much as digits as its factorization.

21307193 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1134, while the sum is 26.

The square root of 21307193 is about 4615.9715120438. The cubic root of 21307193 is about 277.2311840979.

The spelling of 21307193 in words is "twenty-one million, three hundred seven thousand, one hundred ninety-three".