21072960 has 168 divisors, whose sum is σ = 75444096. Its totient is φ = 5598720.

The previous prime is 21072923. The next prime is 21072973. The reversal of 21072960 is 6927012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77625 + ... + 77895.

It is an arithmetic number, because the mean of its divisors is an integer number (449072).

Almost surely, 2^21072960 is an apocalyptic number.

21072960 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 21072960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37722048).

21072960 is an abundant number, since it is smaller than the sum of its proper divisors (54371136).

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

21072960 is an equidigital number, since it uses as much as digits as its factorization.

21072960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303 (or 281 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21072960 is about 4590.5293812370. The cubic root of 21072960 is about 276.2115580231.

Adding to 21072960 its reverse (6927012), we get a palindrome (27999972).

The spelling of 21072960 in words is "twenty-one million, seventy-two thousand, nine hundred sixty".