21273503 has 2 divisors, whose sum is σ = 21273504. Its totient is φ = 21273502.

The previous prime is 21273491. The next prime is 21273509. The reversal of 21273503 is 30537212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21273503 - 2⁴ = 21273487 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21273509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636751 + 10636752.

It is an arithmetic number, because the mean of its divisors is an integer number (10636752).

Almost surely, 2^21273503 is an apocalyptic number.

21273503 is a deficient number, since it is larger than the sum of its proper divisors (1).

21273503 is an equidigital number, since it uses as much as digits as its factorization.

21273503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 21273503 is about 4612.3207824261. The cubic root of 21273503 is about 277.0849917527.

The spelling of 21273503 in words is "twenty-one million, two hundred seventy-three thousand, five hundred three".