216442920989 has 2 divisors, whose sum is σ = 216442920990. Its totient is φ = 216442920988.

The previous prime is 216442920949. The next prime is 216442920997. The reversal of 216442920989 is 989029244612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 210183737764 + 6259183225 = 458458^2 + 79115^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216442920989 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 (216442920949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108221460494 + 108221460495.

It is an arithmetic number, because the mean of its divisors is an integer number (108221460495).

Almost surely, 2^216442920989 is an apocalyptic number.

It is an amenable number.

216442920989 is a deficient number, since it is larger than the sum of its proper divisors (1).

216442920989 is an equidigital number, since it uses as much as digits as its factorization.

216442920989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4478976, while the sum is 56.

The spelling of 216442920989 in words is "two hundred sixteen billion, four hundred forty-two million, nine hundred twenty thousand, nine hundred eighty-nine".