21255360 has 112 divisors (see below), whose sum is σ = 77150976. Its totient is φ = 4856832.

The previous prime is 21255329. The next prime is 21255361. The reversal of 21255360 is 6355212.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21255360.

It is not an unprimeable number, because it can be changed into a prime (21255361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5139 + ... + 8301.

It is an arithmetic number, because the mean of its divisors is an integer number (688848).

Almost surely, 2^21255360 is an apocalyptic number.

21255360 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 21255360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38575488).

21255360 is an abundant number, since it is smaller than the sum of its proper divisors (55895616).

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

21255360 is a wasteful number, since it uses less digits than its factorization.

21255360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3190 (or 3180 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 21255360 is about 4610.3535656173. The cubic root of 21255360 is about 277.0061991688.

The spelling of 21255360 in words is "twenty-one million, two hundred fifty-five thousand, three hundred sixty".