216421603 has 2 divisors, whose sum is σ = 216421604. Its totient is φ = 216421602.

The previous prime is 216421549. The next prime is 216421607. The reversal of 216421603 is 306124612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216421603 is a prime.

It is not a weakly prime, because it can be changed into another prime (216421607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108210801 + 108210802.

It is an arithmetic number, because the mean of its divisors is an integer number (108210802).

Almost surely, 2^216421603 is an apocalyptic number.

216421603 is a deficient number, since it is larger than the sum of its proper divisors (1).

216421603 is an equidigital number, since it uses as much as digits as its factorization.

216421603 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 25.

The square root of 216421603 is about 14711.2746898425. The cubic root of 216421603 is about 600.3901194379.

The spelling of 216421603 in words is "two hundred sixteen million, four hundred twenty-one thousand, six hundred three".