21212131212 has 36 divisors (see below), whose sum is σ = 53961094096. Its totient is φ = 7025672160.

The previous prime is 21212131153. The next prime is 21212131231. The reversal of 21212131212 is 21213121212.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1870864 + ... + 1882167.

Almost surely, 2^21212131212 is an apocalyptic number.

It is an amenable number.

21212131212 is an abundant number, since it is smaller than the sum of its proper divisors (32748962884).

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

21212131212 is a wasteful number, since it uses less digits than its factorization.

21212131212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3753198 (or 3753193 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21212131212 its reverse (21213121212), we get a palindrome (42425252424).

The spelling of 21212131212 in words is "twenty-one billion, two hundred twelve million, one hundred thirty-one thousand, two hundred twelve".