21122393 has 2 divisors, whose sum is σ = 21122394. Its totient is φ = 21122392.

The previous prime is 21122383. The next prime is 21122399. The reversal of 21122393 is 39322112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20403289 + 719104 = 4517^2 + 848^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122393 is a prime.

It is not a weakly prime, because it can be changed into another prime (21122399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561196 + 10561197.

It is an arithmetic number, because the mean of its divisors is an integer number (10561197).

Almost surely, 2^21122393 is an apocalyptic number.

It is an amenable number.

21122393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122393 is an equidigital number, since it uses as much as digits as its factorization.

21122393 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 23.

The square root of 21122393 is about 4595.9104647502. The cubic root of 21122393 is about 276.4273686059.

The spelling of 21122393 in words is "twenty-one million, one hundred twenty-two thousand, three hundred ninety-three".