216129989 has 2 divisors, whose sum is σ = 216129990. Its totient is φ = 216129988.

The previous prime is 216129941. The next prime is 216130009. The reversal of 216129989 is 989921612.

216129989 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., 170093764 + 46036225 = 13042^2 + 6785^2 .

It is a cyclic number.

It is not a de Polignac number, because 216129989 - 2⁸ = 216129733 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 (216123989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108064994 + 108064995.

It is an arithmetic number, because the mean of its divisors is an integer number (108064995).

Almost surely, 2^216129989 is an apocalyptic number.

It is an amenable number.

216129989 is a deficient number, since it is larger than the sum of its proper divisors (1).

216129989 is an equidigital number, since it uses as much as digits as its factorization.

216129989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 47.

The square root of 216129989 is about 14701.3601071465. The cubic root of 216129989 is about 600.1203360490.

The spelling of 216129989 in words is "two hundred sixteen million, one hundred twenty-nine thousand, nine hundred eighty-nine".