21116503 has 2 divisors, whose sum is σ = 21116504. Its totient is φ = 21116502.

The previous prime is 21116479. The next prime is 21116509. The reversal of 21116503 is 30561112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21116503 - 2⁵ = 21116471 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21116509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558251 + 10558252.

It is an arithmetic number, because the mean of its divisors is an integer number (10558252).

Almost surely, 2^21116503 is an apocalyptic number.

21116503 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116503 is an equidigital number, since it uses as much as digits as its factorization.

21116503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21116503 is about 4595.2696330031. The cubic root of 21116503 is about 276.4016722030.

Adding to 21116503 its reverse (30561112), we get a palindrome (51677615).

The spelling of 21116503 in words is "twenty-one million, one hundred sixteen thousand, five hundred three".