216873389 has 2 divisors, whose sum is σ = 216873390. Its totient is φ = 216873388.

The previous prime is 216873383. The next prime is 216873409. The reversal of 216873389 is 983378612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 142396489 + 74476900 = 11933^2 + 8630^2 .

It is a cyclic number.

It is not a de Polignac number, because 216873389 - 2⁴ = 216873373 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216873383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108436694 + 108436695.

It is an arithmetic number, because the mean of its divisors is an integer number (108436695).

Almost surely, 2^216873389 is an apocalyptic number.

It is an amenable number.

216873389 is a deficient number, since it is larger than the sum of its proper divisors (1).

216873389 is an equidigital number, since it uses as much as digits as its factorization.

216873389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 47.

The square root of 216873389 is about 14726.6217782627. The cubic root of 216873389 is about 600.8076059851.

It can be divided in two parts, 2168 and 73389, that added together give a palindrome (75557).

The spelling of 216873389 in words is "two hundred sixteen million, eight hundred seventy-three thousand, three hundred eighty-nine".