243215061205681 has 2 divisors, whose sum is σ = 243215061205682. Its totient is φ = 243215061205680.

The previous prime is 243215061205577. The next prime is 243215061205759. The reversal of 243215061205681 is 186502160512342.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180076002177600 + 63139059028081 = 13419240^2 + 7946009^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243215061205681 is a prime.

It is a super-2 number, since 2×243215061205681² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (243215061205981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121607530602840 + 121607530602841.

It is an arithmetic number, because the mean of its divisors is an integer number (121607530602841).

Almost surely, 2^{243215061205681} is an apocalyptic number.

It is an amenable number.

243215061205681 is a deficient number, since it is larger than the sum of its proper divisors (1).

243215061205681 is an equidigital number, since it uses as much as digits as its factorization.

243215061205681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 691200, while the sum is 46.

The spelling of 243215061205681 in words is "two hundred forty-three trillion, two hundred fifteen billion, sixty-one million, two hundred five thousand, six hundred eighty-one".