21218081212 has 24 divisors (see below), whose sum is σ = 37689775200. Its totient is φ = 10450641600.

The previous prime is 21218081189. The next prime is 21218081221.

21218081212 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53712 + ... + 212887.

It is an arithmetic number, because the mean of its divisors is an integer number (1570407300).

Almost surely, 2^21218081212 is an apocalyptic number.

It is an amenable number.

21218081212 is a deficient number, since it is larger than the sum of its proper divisors (16471693988).

21218081212 is a wasteful number, since it uses less digits than its factorization.

21218081212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266901 (or 266899 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 28.

It can be divided in two parts, 212180 and 81212, that added together give a palindrome (293392).

The spelling of 21218081212 in words is "twenty-one billion, two hundred eighteen million, eighty-one thousand, two hundred twelve".