21306654720 has 900 divisors, whose sum is σ = 87067161720. Its totient is φ = 4968677376.

The previous prime is 21306654679. The next prime is 21306654799. The reversal of 21306654720 is 2745660312.

21306654720 is a `hidden beast` number, since 2 + 1 + 30 + 66 + 547 + 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 an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1121402871 + ... + 1121402889.

Almost surely, 2^21306654720 is an apocalyptic number.

21306654720 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 21306654720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43533580860).

21306654720 is an abundant number, since it is smaller than the sum of its proper divisors (65760507000).

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

21306654720 is an equidigital number, since it uses as much as digits as its factorization.

21306654720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 42 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 21306654720 in words is "twenty-one billion, three hundred six million, six hundred fifty-four thousand, seven hundred twenty".