21366593 has 2 divisors, whose sum is σ = 21366594. Its totient is φ = 21366592.

The previous prime is 21366581. The next prime is 21366619. The reversal of 21366593 is 39566312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19642624 + 1723969 = 4432^2 + 1313^2 .

It is a cyclic number.

It is not a de Polignac number, because 21366593 - 2¹⁰ = 21365569 is a prime.

It is not a weakly prime, because it can be changed into another prime (21366503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10683296 + 10683297.

It is an arithmetic number, because the mean of its divisors is an integer number (10683297).

Almost surely, 2^21366593 is an apocalyptic number.

It is an amenable number.

21366593 is a deficient number, since it is larger than the sum of its proper divisors (1).

21366593 is an equidigital number, since it uses as much as digits as its factorization.

21366593 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 35.

The square root of 21366593 is about 4622.4012158185. The cubic root of 21366593 is about 277.4885659331.

The spelling of 21366593 in words is "twenty-one million, three hundred sixty-six thousand, five hundred ninety-three".