243741989 has 2 divisors, whose sum is σ = 243741990. Its totient is φ = 243741988.

The previous prime is 243741959. The next prime is 243741991. The reversal of 243741989 is 989147342.

243741989 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., 243048100 + 693889 = 15590^2 + 833^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243741989 is a prime.

It is a super-2 number, since 2×243741989² = 118820314403352242, which contains 22 as substring.

Together with 243741991, 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 (243741919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121870994 + 121870995.

It is an arithmetic number, because the mean of its divisors is an integer number (121870995).

Almost surely, 2^243741989 is an apocalyptic number.

It is an amenable number.

243741989 is a deficient number, since it is larger than the sum of its proper divisors (1).

243741989 is an equidigital number, since it uses as much as digits as its factorization.

243741989 is an evil number, because the sum of its binary digits is even.

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

The square root of 243741989 is about 15612.2384365600. The cubic root of 243741989 is about 624.6596453009.

The spelling of 243741989 in words is "two hundred forty-three million, seven hundred forty-one thousand, nine hundred eighty-nine".