21087203 has 2 divisors, whose sum is σ = 21087204. Its totient is φ = 21087202.

The previous prime is 21087197. The next prime is 21087211. The reversal of 21087203 is 30278012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21087203 - 2¹⁰ = 21086179 is a prime.

It is not a weakly prime, because it can be changed into another prime (21087403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10543601 + 10543602.

It is an arithmetic number, because the mean of its divisors is an integer number (10543602).

Almost surely, 2^21087203 is an apocalyptic number.

21087203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21087203 is an equidigital number, since it uses as much as digits as its factorization.

21087203 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21087203 is about 4592.0804653229. The cubic root of 21087203 is about 276.2737735388.

The spelling of 21087203 in words is "twenty-one million, eighty-seven thousand, two hundred three".