21297203 has 2 divisors, whose sum is σ = 21297204. Its totient is φ = 21297202.

The previous prime is 21297193. The next prime is 21297247. The reversal of 21297203 is 30279212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21297203 - 2⁶ = 21297139 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21297293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10648601 + 10648602.

It is an arithmetic number, because the mean of its divisors is an integer number (10648602).

Almost surely, 2^21297203 is an apocalyptic number.

21297203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21297203 is an equidigital number, since it uses as much as digits as its factorization.

21297203 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21297203 is about 4614.8892727778. The cubic root of 21297203 is about 277.1878501796.

Subtracting 21297203 from its reverse (30279212), we obtain a square (8982009 = 2997²).

The spelling of 21297203 in words is "twenty-one million, two hundred ninety-seven thousand, two hundred three".