21180724992 has 360 divisors, whose sum is σ = 72560904416. Its totient is φ = 6019743744.

The previous prime is 21180724991. The next prime is 21180725003. The reversal of 21180724992 is 29942708112.

21180724992 is a `hidden beast` number, since 2 + 11 + 80 + 72 + 499 + 2 = 666.

It is a super-2 number, since 2×21180724992² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21180724991) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 48916008 + ... + 48916440.

Almost surely, 2^21180724992 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 21180724992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36280452208).

21180724992 is an abundant number, since it is smaller than the sum of its proper divisors (51380179424).

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

21180724992 is an equidigital number, since it uses as much as digits as its factorization.

21180724992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 805 (or 782 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The spelling of 21180724992 in words is "twenty-one billion, one hundred eighty million, seven hundred twenty-four thousand, nine hundred ninety-two".