21135360 has 128 divisors (see below), whose sum is σ = 69204960. Its totient is φ = 5505024.

The previous prime is 21135349. The next prime is 21135371. The reversal of 21135360 is 6353112.

It is an interprime number because it is at equal distance from previous prime (21135349) and next prime (21135371).

It is a tau number, because it is divible by the number of its divisors (128).

It is a zygodrome in base 4.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 491499 + ... + 491541.

Almost surely, 2^21135360 is an apocalyptic number.

21135360 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 21135360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34602480).

21135360 is an abundant number, since it is smaller than the sum of its proper divisors (48069600).

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

21135360 is an frugal number, since it uses more digits than its factorization.

21135360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 53 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 21135360 is about 4597.3209589934. The cubic root of 21135360 is about 276.4839231268.

Adding to 21135360 its reverse (6353112), we get a palindrome (27488472).

The spelling of 21135360 in words is "twenty-one million, one hundred thirty-five thousand, three hundred sixty".