21218112354 has 16 divisors (see below), whose sum is σ = 42438782592. Its totient is φ = 7072277808.

The previous prime is 21218112341. The next prime is 21218112359. The reversal of 21218112354 is 45321181212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21218112359) 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 7 ways as a sum of consecutive naturals, for example, 11287 + ... + 206309.

It is an arithmetic number, because the mean of its divisors is an integer number (2652423912).

Almost surely, 2^21218112354 is an apocalyptic number.

21218112354 is an abundant number, since it is smaller than the sum of its proper divisors (21220670238).

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

21218112354 is a wasteful number, since it uses less digits than its factorization.

21218112354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213161.

The product of its digits is 3840, while the sum is 30.

Adding to 21218112354 its reverse (45321181212), we get a palindrome (66539293566).

The spelling of 21218112354 in words is "twenty-one billion, two hundred eighteen million, one hundred twelve thousand, three hundred fifty-four".