21943193 has 2 divisors, whose sum is σ = 21943194. Its totient is φ = 21943192.

The previous prime is 21943177. The next prime is 21943199. The reversal of 21943193 is 39134912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18939904 + 3003289 = 4352^2 + 1733^2 .

It is a cyclic number.

It is not a de Polignac number, because 21943193 - 2⁴ = 21943177 is a prime.

It is not a weakly prime, because it can be changed into another prime (21943199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10971596 + 10971597.

It is an arithmetic number, because the mean of its divisors is an integer number (10971597).

Almost surely, 2^21943193 is an apocalyptic number.

It is an amenable number.

21943193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21943193 is an equidigital number, since it uses as much as digits as its factorization.

21943193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 32.

The square root of 21943193 is about 4684.3561990950. The cubic root of 21943193 is about 279.9625502635.

The spelling of 21943193 in words is "twenty-one million, nine hundred forty-three thousand, one hundred ninety-three".