21255462720 has 672 divisors, whose sum is σ = 79682279040. Its totient is φ = 5388042240.

The previous prime is 21255462713. The next prime is 21255462721. The reversal of 21255462720 is 2726455212.

21255462720 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 5 + 4 + 627 + 20 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255462721) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 188101384 + ... + 188101496.

It is an arithmetic number, because the mean of its divisors is an integer number (118574820).

Almost surely, 2^21255462720 is an apocalyptic number.

21255462720 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 21255462720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39841139520).

21255462720 is an abundant number, since it is smaller than the sum of its proper divisors (58426816320).

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

21255462720 is a wasteful number, since it uses less digits than its factorization.

21255462720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 36.

The spelling of 21255462720 in words is "twenty-one billion, two hundred fifty-five million, four hundred sixty-two thousand, seven hundred twenty".