21409671312 has 120 divisors (see below), whose sum is σ = 62297352000. Its totient is φ = 6855577344.

The previous prime is 21409671277. The next prime is 21409671313. The reversal of 21409671312 is 21317690412.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21409671313) 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, 818143 + ... + 843905.

It is an arithmetic number, because the mean of its divisors is an integer number (519144600).

Almost surely, 2^21409671312 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 21409671312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31148676000).

21409671312 is an abundant number, since it is smaller than the sum of its proper divisors (40887680688).

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

21409671312 is a wasteful number, since it uses less digits than its factorization.

21409671312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26005 (or 25996 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The spelling of 21409671312 in words is "twenty-one billion, four hundred nine million, six hundred seventy-one thousand, three hundred twelve".