21473944128 has 896 divisors, whose sum is σ = 85412275200. Its totient is φ = 5127929856.

The previous prime is 21473944123. The next prime is 21473944147. The reversal of 21473944128 is 82144937412.

21473944128 is a `hidden beast` number, since 2 + 147 + 3 + 94 + 412 + 8 = 666.

It is a super-2 number, since 2×21473944128² (a number of 21 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21473944123) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 77523126 + ... + 77523402.

It is an arithmetic number, because the mean of its divisors is an integer number (95326200).

Almost surely, 2^21473944128 is an apocalyptic number.

21473944128 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21473944128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42706137600).

21473944128 is an abundant number, since it is smaller than the sum of its proper divisors (63938331072).

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

21473944128 is a wasteful number, since it uses less digits than its factorization.

21473944128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364 (or 348 counting only the distinct ones).

The product of its digits is 387072, while the sum is 45.

The spelling of 21473944128 in words is "twenty-one billion, four hundred seventy-three million, nine hundred forty-four thousand, one hundred twenty-eight".