21294436072 has 128 divisors (see below), whose sum is σ = 50275008000. Its totient is φ = 8402171904.

The previous prime is 21294436061. The next prime is 21294436073. The reversal of 21294436072 is 27063449212.

It is not an unprimeable number, because it can be changed into a prime (21294436073) 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, 24006813 + ... + 24007699.

It is an arithmetic number, because the mean of its divisors is an integer number (392773500).

Almost surely, 2^21294436072 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 21294436072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25137504000).

21294436072 is an abundant number, since it is smaller than the sum of its proper divisors (28980571928).

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

21294436072 is a wasteful number, since it uses less digits than its factorization.

21294436072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1600 (or 1582 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 40.

The spelling of 21294436072 in words is "twenty-one billion, two hundred ninety-four million, four hundred thirty-six thousand, seventy-two".