21232123218 has 40 divisors (see below), whose sum is σ = 47598483900. Its totient is φ = 7073982720.

The previous prime is 21232123217. The next prime is 21232123223. The reversal of 21232123218 is 81232123212.

21232123218 is a `hidden beast` number, since 2 + 12 + 321 + 2 + 321 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 19452717729 + 1779405489 = 139473^2 + 42183^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21232123191 and 21232123200.

It is not an unprimeable number, because it can be changed into a prime (21232123217) 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 19 ways as a sum of consecutive naturals, for example, 319758 + ... + 380406.

Almost surely, 2^21232123218 is an apocalyptic number.

21232123218 is an abundant number, since it is smaller than the sum of its proper divisors (26366360682).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21232123218 is a wasteful number, since it uses less digits than its factorization.

21232123218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62824 (or 62815 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The spelling of 21232123218 in words is "twenty-one billion, two hundred thirty-two million, one hundred twenty-three thousand, two hundred eighteen".