243320510981 has 2 divisors, whose sum is σ = 243320510982. Its totient is φ = 243320510980.

The previous prime is 243320510957. The next prime is 243320510987. The reversal of 243320510981 is 189015023342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 241089838081 + 2230672900 = 491009^2 + 47230^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243320510981 is a prime.

It is a super-2 number, since 2×243320510981² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243320510987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121660255490 + 121660255491.

It is an arithmetic number, because the mean of its divisors is an integer number (121660255491).

Almost surely, 2^243320510981 is an apocalyptic number.

It is an amenable number.

243320510981 is a deficient number, since it is larger than the sum of its proper divisors (1).

243320510981 is an equidigital number, since it uses as much as digits as its factorization.

243320510981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 38.

The spelling of 243320510981 in words is "two hundred forty-three billion, three hundred twenty million, five hundred ten thousand, nine hundred eighty-one".