21381203 has 2 divisors, whose sum is σ = 21381204. Its totient is φ = 21381202.

The previous prime is 21381181. The next prime is 21381209. The reversal of 21381203 is 30218312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21381203 - 2²⁴ = 4603987 is a prime.

It is a Chen prime.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (21381209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10690601 + 10690602.

It is an arithmetic number, because the mean of its divisors is an integer number (10690602).

Almost surely, 2^21381203 is an apocalyptic number.

21381203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21381203 is an equidigital number, since it uses as much as digits as its factorization.

21381203 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21381203 is about 4623.9812932148. The cubic root of 21381203 is about 277.5517983549.

Adding to 21381203 its reverse (30218312), we get a palindrome (51599515).

The spelling of 21381203 in words is "twenty-one million, three hundred eighty-one thousand, two hundred three".