21581725681152 has 3600 divisors, whose sum is σ = 89119054265472. Its totient is φ = 5146880901120.

The previous prime is 21581725681151. The next prime is 21581725681157. The reversal of 21581725681152 is 25118652718512.

21581725681152 is a `hidden beast` number, since 2 + 1 + 5 + 8 + 1 + 72 + 568 + 1 + 1 + 5 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21581725681151) by changing a digit.

It is a polite number, since it can be written in 359 ways as a sum of consecutive naturals, for example, 295640077788 + ... + 295640077860.

Almost surely, 2^{21581725681152} 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 21581725681152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44559527132736).

21581725681152 is an abundant number, since it is smaller than the sum of its proper divisors (67537328584320).

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

21581725681152 is a wasteful number, since it uses less digits than its factorization.

21581725681152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 148 counting only the distinct ones).

The product of its digits is 2688000, while the sum is 54.

The spelling of 21581725681152 in words is "twenty-one trillion, five hundred eighty-one billion, seven hundred twenty-five million, six hundred eighty-one thousand, one hundred fifty-two".