21138353 has 2 divisors, whose sum is σ = 21138354. Its totient is φ = 21138352.

The previous prime is 21138319. The next prime is 21138367. The reversal of 21138353 is 35383112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19642624 + 1495729 = 4432^2 + 1223^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21138353 is a prime.

It is not a weakly prime, because it can be changed into another prime (21138053) 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, 10569176 + 10569177.

It is an arithmetic number, because the mean of its divisors is an integer number (10569177).

Almost surely, 2^21138353 is an apocalyptic number.

It is an amenable number.

21138353 is a deficient number, since it is larger than the sum of its proper divisors (1).

21138353 is an equidigital number, since it uses as much as digits as its factorization.

21138353 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 26.

The square root of 21138353 is about 4597.6464631374. The cubic root of 21138353 is about 276.4969735680.

The spelling of 21138353 in words is "twenty-one million, one hundred thirty-eight thousand, three hundred fifty-three".