21102001212 has 12 divisors (see below), whose sum is σ = 49238002856. Its totient is φ = 7034000400.

The previous prime is 21102001187. The next prime is 21102001229. The reversal of 21102001212 is 21210020112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Harshad number since it is a multiple of its sum of digits (12), and also a Moran number because the ratio is a prime number: 1758500101 = 21102001212 / (2 + 1 + 1 + 0 + 2 + 0 + 0 + 1 + 2 + 1 + 2).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 879250039 + ... + 879250062.

Almost surely, 2^21102001212 is an apocalyptic number.

It is an amenable number.

21102001212 is an abundant number, since it is smaller than the sum of its proper divisors (28136001644).

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

21102001212 is a wasteful number, since it uses less digits than its factorization.

21102001212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1758500108 (or 1758500106 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21102001212 its reverse (21210020112), we get a palindrome (42312021324).

The spelling of 21102001212 in words is "twenty-one billion, one hundred two million, one thousand, two hundred twelve".