21003271 has 2 divisors, whose sum is σ = 21003272. Its totient is φ = 21003270.

The previous prime is 21003259. The next prime is 21003293. The reversal of 21003271 is 17230012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21003271 is a prime.

It is a super-2 number, since 2×21003271² = 882274785398882, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21003371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501635 + 10501636.

It is an arithmetic number, because the mean of its divisors is an integer number (10501636).

Almost surely, 2^21003271 is an apocalyptic number.

21003271 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003271 is an equidigital number, since it uses as much as digits as its factorization.

21003271 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21003271 is about 4582.9325764187. The cubic root of 21003271 is about 275.9067414039.

Adding to 21003271 its reverse (17230012), we get a palindrome (38233283).

The spelling of 21003271 in words is "twenty-one million, three thousand, two hundred seventy-one".