243181381 has 4 divisors (see below), whose sum is σ = 243227872. Its totient is φ = 243134892.

The previous prime is 243181363. The next prime is 243181387. The reversal of 243181381 is 183181342.

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 a cyclic number.

It is not a de Polignac number, because 243181381 - 2⁵ = 243181349 is a prime.

It is a super-2 number, since 2×243181381² = 118274368130134322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243181387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14235 + ... + 26248.

It is an arithmetic number, because the mean of its divisors is an integer number (60806968).

Almost surely, 2^243181381 is an apocalyptic number.

It is an amenable number.

243181381 is a deficient number, since it is larger than the sum of its proper divisors (46491).

243181381 is an equidigital number, since it uses as much as digits as its factorization.

243181381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46490.

The product of its digits is 4608, while the sum is 31.

The square root of 243181381 is about 15594.2739811766. The cubic root of 243181381 is about 624.1803707224.

The spelling of 243181381 in words is "two hundred forty-three million, one hundred eighty-one thousand, three hundred eighty-one".