21689393712 has 160 divisors (see below), whose sum is σ = 67596864000. Its totient is φ = 5983149312.

The previous prime is 21689393711. The next prime is 21689393729. The reversal of 21689393712 is 21739398612.

It is not an unprimeable number, because it can be changed into a prime (21689393711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 454743 + ... + 500169.

It is an arithmetic number, because the mean of its divisors is an integer number (422480400).

Almost surely, 2^21689393712 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 21689393712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33798432000).

21689393712 is an abundant number, since it is smaller than the sum of its proper divisors (45907470288).

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

21689393712 is a wasteful number, since it uses less digits than its factorization.

21689393712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45488 (or 45468 counting only the distinct ones).

The product of its digits is 979776, while the sum is 51.

The spelling of 21689393712 in words is "twenty-one billion, six hundred eighty-nine million, three hundred ninety-three thousand, seven hundred twelve".