21209091212 has 12 divisors (see below), whose sum is σ = 37343615736. Its totient is φ = 10539486720.

The previous prime is 21209091209. The next prime is 21209091263. The reversal of 21209091212 is 21219090212.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16263989 + ... + 16265292.

It is an arithmetic number, because the mean of its divisors is an integer number (3111967978).

Almost surely, 2^21209091212 is an apocalyptic number.

It is an amenable number.

21209091212 is a deficient number, since it is larger than the sum of its proper divisors (16134524524).

21209091212 is a wasteful number, since it uses less digits than its factorization.

21209091212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32529448 (or 32529446 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 29.

The spelling of 21209091212 in words is "twenty-one billion, two hundred nine million, ninety-one thousand, two hundred twelve".