216673421 has 2 divisors, whose sum is σ = 216673422. Its totient is φ = 216673420.

The previous prime is 216673399. The next prime is 216673423. The reversal of 216673421 is 124376612.

216673421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 168870025 + 47803396 = 12995^2 + 6914^2 .

It is a cyclic number.

It is not a de Polignac number, because 216673421 - 2⁶ = 216673357 is a prime.

Together with 216673423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216673423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108336710 + 108336711.

It is an arithmetic number, because the mean of its divisors is an integer number (108336711).

Almost surely, 2^216673421 is an apocalyptic number.

It is an amenable number.

216673421 is a deficient number, since it is larger than the sum of its proper divisors (1).

216673421 is an equidigital number, since it uses as much as digits as its factorization.

216673421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 32.

The square root of 216673421 is about 14719.8308753871. The cubic root of 216673421 is about 600.6228910837.

The spelling of 216673421 in words is "two hundred sixteen million, six hundred seventy-three thousand, four hundred twenty-one".