243121522981 has 2 divisors, whose sum is σ = 243121522982. Its totient is φ = 243121522980.

The previous prime is 243121522937. The next prime is 243121523053. The reversal of 243121522981 is 189225121342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 224894092900 + 18227430081 = 474230^2 + 135009^2 .

It is a cyclic number.

It is not a de Polignac number, because 243121522981 - 2³¹ = 240974039333 is a prime.

It is a super-2 number, since 2×243121522981² (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 (243121522481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121560761490 + 121560761491.

It is an arithmetic number, because the mean of its divisors is an integer number (121560761491).

Almost surely, 2^243121522981 is an apocalyptic number.

It is an amenable number.

243121522981 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121522981 is an equidigital number, since it uses as much as digits as its factorization.

243121522981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 40.

The spelling of 243121522981 in words is "two hundred forty-three billion, one hundred twenty-one million, five hundred twenty-two thousand, nine hundred eighty-one".