243121881 has 4 divisors (see below), whose sum is σ = 324162512. Its totient is φ = 162081252.

The previous prime is 243121861. The next prime is 243121903. The reversal of 243121881 is 188121342.

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.

It is not a de Polignac number, because 243121881 - 2¹⁴ = 243105497 is a prime.

It is a super-2 number, since 2×243121881² = 118216498041956322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243121861) 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, 40520311 + ... + 40520316.

It is an arithmetic number, because the mean of its divisors is an integer number (81040628).

Almost surely, 2^243121881 is an apocalyptic number.

It is an amenable number.

243121881 is a deficient number, since it is larger than the sum of its proper divisors (81040631).

243121881 is an equidigital number, since it uses as much as digits as its factorization.

243121881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81040630.

The product of its digits is 3072, while the sum is 30.

The square root of 243121881 is about 15592.3661129413. The cubic root of 243121881 is about 624.1294598053.

The spelling of 243121881 in words is "two hundred forty-three million, one hundred twenty-one thousand, eight hundred eighty-one".