21329760 has 96 divisors (see below), whose sum is σ = 69062112. Its totient is φ = 5529600.

The previous prime is 21329719. The next prime is 21329773. The reversal of 21329760 is 6792312.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a zygodrome in base 9.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17160 + ... + 18360.

It is an arithmetic number, because the mean of its divisors is an integer number (719397).

Almost surely, 2^21329760 is an apocalyptic number.

21329760 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 21329760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34531056).

21329760 is an abundant number, since it is smaller than the sum of its proper divisors (47732352).

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

21329760 is a wasteful number, since it uses less digits than its factorization.

21329760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1256 (or 1248 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 21329760 is about 4618.4153126370. The cubic root of 21329760 is about 277.3290238071.

The spelling of 21329760 in words is "twenty-one million, three hundred twenty-nine thousand, seven hundred sixty".