21008960 has 112 divisors (see below), whose sum is σ = 58375296. Its totient is φ = 7053312.

The previous prime is 21008941. The next prime is 21009017. The reversal of 21008960 is 6980012.

It is a tau number, because it is divible by the number of its divisors (112).

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, 185864 + ... + 185976.

It is an arithmetic number, because the mean of its divisors is an integer number (521208).

Almost surely, 2^21008960 is an apocalyptic number.

21008960 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 21008960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29187648).

21008960 is an abundant number, since it is smaller than the sum of its proper divisors (37366336).

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

21008960 is a wasteful number, since it uses less digits than its factorization.

21008960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21008960 is about 4583.5532068473. The cubic root of 21008960 is about 275.9316500916.

Adding to 21008960 its reverse (6980012), we get a palindrome (27988972).

The spelling of 21008960 in words is "twenty-one million, eight thousand, nine hundred sixty".