21038393 has 2 divisors, whose sum is σ = 21038394. Its totient is φ = 21038392.

The previous prime is 21038389. The next prime is 21038419. The reversal of 21038393 is 39383012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19963024 + 1075369 = 4468^2 + 1037^2 .

It is a cyclic number.

It is not a de Polignac number, because 21038393 - 2² = 21038389 is a prime.

It is a super-2 number, since 2×21038393² = 885227960044898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21038323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10519196 + 10519197.

It is an arithmetic number, because the mean of its divisors is an integer number (10519197).

Almost surely, 2^21038393 is an apocalyptic number.

It is an amenable number.

21038393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21038393 is an equidigital number, since it uses as much as digits as its factorization.

21038393 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 21038393 is about 4586.7628018026. The cubic root of 21038393 is about 276.0604476228.

The spelling of 21038393 in words is "twenty-one million, thirty-eight thousand, three hundred ninety-three".