21209703312 has 120 divisors (see below), whose sum is σ = 64689106656. Its totient is φ = 5969424384.

The previous prime is 21209703311. The next prime is 21209703329. The reversal of 21209703312 is 21330790212.

It is a self number, because there is not a number n which added to its sum of digits gives 21209703312.

It is not an unprimeable number, because it can be changed into a prime (21209703311) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 90288 + ... + 224880.

Almost surely, 2^21209703312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21209703312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32344553328).

21209703312 is an abundant number, since it is smaller than the sum of its proper divisors (43479403344).

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

21209703312 is a wasteful number, since it uses less digits than its factorization.

21209703312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134685 (or 134672 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 30.

The spelling of 21209703312 in words is "twenty-one billion, two hundred nine million, seven hundred three thousand, three hundred twelve".