21829760 has 64 divisors (see below), whose sum is σ = 54492480. Its totient is φ = 8346624.

The previous prime is 21829729. The next prime is 21829763. The reversal of 21829760 is 6792812.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21829760.

It is not an unprimeable number, because it can be changed into a prime (21829763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13979 + ... + 15461.

It is an arithmetic number, because the mean of its divisors is an integer number (851445).

Almost surely, 2^21829760 is an apocalyptic number.

21829760 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 21829760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27246240).

21829760 is an abundant number, since it is smaller than the sum of its proper divisors (32662720).

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

21829760 is a wasteful number, since it uses less digits than its factorization.

21829760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525 (or 1513 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 21829760 is about 4672.2328709087. The cubic root of 21829760 is about 279.4793044094.

The spelling of 21829760 in words is "twenty-one million, eight hundred twenty-nine thousand, seven hundred sixty".