21503063 has 2 divisors, whose sum is σ = 21503064. Its totient is φ = 21503062.

The previous prime is 21503051. The next prime is 21503071. The reversal of 21503063 is 36030512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21503063 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 (21503033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10751531 + 10751532.

It is an arithmetic number, because the mean of its divisors is an integer number (10751532).

Almost surely, 2^21503063 is an apocalyptic number.

21503063 is a deficient number, since it is larger than the sum of its proper divisors (1).

21503063 is an equidigital number, since it uses as much as digits as its factorization.

21503063 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 21503063 is about 4637.1395277692. The cubic root of 21503063 is about 278.0780925479.

Adding to 21503063 its reverse (36030512), we get a palindrome (57533575).

The spelling of 21503063 in words is "twenty-one million, five hundred three thousand, sixty-three".