21201212112 has 40 divisors (see below), whose sum is σ = 54851263104. Its totient is φ = 7056559104.

The previous prime is 21201212051. The next prime is 21201212143. The reversal of 21201212112 is 21121210212.

It is a junction number, because it is equal to n+sod(n) for n = 21201212091 and 21201212100.

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, 295848 + ... + 360455.

Almost surely, 2^21201212112 is an apocalyptic number.

It is an amenable number.

21201212112 is an abundant number, since it is smaller than the sum of its proper divisors (33650050992).

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

21201212112 is a wasteful number, since it uses less digits than its factorization.

21201212112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656987 (or 656981 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21201212112 its reverse (21121210212), we get a palindrome (42322422324).

The spelling of 21201212112 in words is "twenty-one billion, two hundred one million, two hundred twelve thousand, one hundred twelve".