23181813 has 6 divisors (see below), whose sum is σ = 33484854. Its totient is φ = 15454536.

The previous prime is 23181797. The next prime is 23181883. The reversal of 23181813 is 31818132.

It can be written as a sum of positive squares in only one way, i.e., 18173169 + 5008644 = 4263^2 + 2238^2 .

It is not a de Polignac number, because 23181813 - 2⁴ = 23181797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23181883) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1287870 + ... + 1287887.

It is an arithmetic number, because the mean of its divisors is an integer number (5580809).

Almost surely, 2^23181813 is an apocalyptic number.

It is an amenable number.

23181813 is a deficient number, since it is larger than the sum of its proper divisors (10303041).

23181813 is a wasteful number, since it uses less digits than its factorization.

23181813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2575763 (or 2575760 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 23181813 is about 4814.7495261955. The cubic root of 23181813 is about 285.1340827998.

Adding to 23181813 its reverse (31818132), we get a palindrome (54999945).

The spelling of 23181813 in words is "twenty-three million, one hundred eighty-one thousand, eight hundred thirteen".