21147264 has 128 divisors (see below), whose sum is σ = 64872000. Its totient is φ = 6773760.

The previous prime is 21147257. The next prime is 21147283. The reversal of 21147264 is 46274112.

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

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 100119 + ... + 100329.

Almost surely, 2^21147264 is an apocalyptic number.

21147264 is a gapful number since it is divisible by the number (24) 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 21147264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32436000).

21147264 is an abundant number, since it is smaller than the sum of its proper divisors (43724736).

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

21147264 is a wasteful number, since it uses less digits than its factorization.

21147264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263 (or 245 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 21147264 is about 4598.6154438048. The cubic root of 21147264 is about 276.5358210978.

The spelling of 21147264 in words is "twenty-one million, one hundred forty-seven thousand, two hundred sixty-four".