216121889 has 2 divisors, whose sum is σ = 216121890. Its totient is φ = 216121888.

The previous prime is 216121883. The next prime is 216121931. The reversal of 216121889 is 988121612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130873600 + 85248289 = 11440^2 + 9233^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216121889 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216121883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108060944 + 108060945.

It is an arithmetic number, because the mean of its divisors is an integer number (108060945).

Almost surely, 2^216121889 is an apocalyptic number.

It is an amenable number.

216121889 is a deficient number, since it is larger than the sum of its proper divisors (1).

216121889 is an equidigital number, since it uses as much as digits as its factorization.

216121889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 38.

The square root of 216121889 is about 14701.0846198503. The cubic root of 216121889 is about 600.1128389628.

The spelling of 216121889 in words is "two hundred sixteen million, one hundred twenty-one thousand, eight hundred eighty-nine".