243256536161 has 4 divisors (see below), whose sum is σ = 243260094000. Its totient is φ = 243252978324.

The previous prime is 243256536143. The next prime is 243256536163. The reversal of 243256536161 is 161635652342.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 161635652342 = 2 ⋅80817826171.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243256536161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243256536163) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1674311 + ... + 1813788.

It is an arithmetic number, because the mean of its divisors is an integer number (60815023500).

Almost surely, 2^243256536161 is an apocalyptic number.

It is an amenable number.

243256536161 is a deficient number, since it is larger than the sum of its proper divisors (3557839).

243256536161 is an equidigital number, since it uses as much as digits as its factorization.

243256536161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3557838.

The product of its digits is 777600, while the sum is 44.

The spelling of 243256536161 in words is "two hundred forty-three billion, two hundred fifty-six million, five hundred thirty-six thousand, one hundred sixty-one".