21444272640 has 1280 divisors, whose sum is σ = 95033917440. Its totient is φ = 4476764160.

The previous prime is 21444272627. The next prime is 21444272659. The reversal of 21444272640 is 4627244412.

21444272640 is a `hidden beast` number, since 2 + 1 + 4 + 4 + 4 + 2 + 7 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (1280).

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

It is a junction number, because it is equal to n+sod(n) for n = 21444272595 and 21444272604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 456261097 + ... + 456261143.

It is an arithmetic number, because the mean of its divisors is an integer number (74245248).

Almost surely, 2^21444272640 is an apocalyptic number.

21444272640 is a gapful number since it is divisible by the number (20) 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 21444272640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47516958720).

21444272640 is an abundant number, since it is smaller than the sum of its proper divisors (73589644800).

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

21444272640 is a wasteful number, since it uses less digits than its factorization.

21444272640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 36.

The spelling of 21444272640 in words is "twenty-one billion, four hundred forty-four million, two hundred seventy-two thousand, six hundred forty".