21725256672 has 192 divisors, whose sum is σ = 72900172800. Its totient is φ = 6165849600.

The previous prime is 21725256647. The next prime is 21725256673. The reversal of 21725256672 is 27665252712.

21725256672 is a `hidden beast` number, since 2 + 17 + 2 + 5 + 2 + 566 + 72 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21725256673) 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, 901354 + ... + 925142.

It is an arithmetic number, because the mean of its divisors is an integer number (379688400).

Almost surely, 2^21725256672 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 21725256672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36450086400).

21725256672 is an abundant number, since it is smaller than the sum of its proper divisors (51174916128).

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

21725256672 is a wasteful number, since it uses less digits than its factorization.

21725256672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23966 (or 23952 counting only the distinct ones).

The product of its digits is 705600, while the sum is 45.

The spelling of 21725256672 in words is "twenty-one billion, seven hundred twenty-five million, two hundred fifty-six thousand, six hundred seventy-two".