21530774720 has 896 divisors, whose sum is σ = 73147318272. Its totient is φ = 5839257600.

The previous prime is 21530774633. The next prime is 21530774753. The reversal of 21530774720 is 2747703512.

It is a super-3 number, since 3×21530774720³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 352963490 + ... + 352963550.

It is an arithmetic number, because the mean of its divisors is an integer number (81637632).

Almost surely, 2^21530774720 is an apocalyptic number.

21530774720 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 21530774720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36573659136).

21530774720 is an abundant number, since it is smaller than the sum of its proper divisors (51616543552).

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

21530774720 is a wasteful number, since it uses less digits than its factorization.

21530774720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 82320, while the sum is 38.

The spelling of 21530774720 in words is "twenty-one billion, five hundred thirty million, seven hundred seventy-four thousand, seven hundred twenty".