21608603 has 2 divisors, whose sum is σ = 21608604. Its totient is φ = 21608602.

The previous prime is 21608551. The next prime is 21608611. The reversal of 21608603 is 30680612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21608603 - 2⁸ = 21608347 is a prime.

It is a super-2 number, since 2×21608603² = 933863447223218, which contains 22 as substring.

It is equal to p_1366028 and since 21608603 and 1366028 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21608623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10804301 + 10804302.

It is an arithmetic number, because the mean of its divisors is an integer number (10804302).

Almost surely, 2^21608603 is an apocalyptic number.

21608603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21608603 is an equidigital number, since it uses as much as digits as its factorization.

21608603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21608603 is about 4648.5054587469. The cubic root of 21608603 is about 278.5322988024.

The spelling of 21608603 in words is "twenty-one million, six hundred eight thousand, six hundred three".