21270288 has 80 divisors (see below), whose sum is σ = 59996160. Its totient is φ = 6454272.

The previous prime is 21270269. The next prime is 21270299. The reversal of 21270288 is 88207212.

It is a happy number.

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, 55345 + ... + 55727.

It is an arithmetic number, because the mean of its divisors is an integer number (749952).

Almost surely, 2^21270288 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21270288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29998080).

21270288 is an abundant number, since it is smaller than the sum of its proper divisors (38725872).

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

21270288 is a wasteful number, since it uses less digits than its factorization.

21270288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 21270288 is about 4611.9722462305. The cubic root of 21270288 is about 277.0710327113.

It can be divided in two parts, 212 and 70288, that added together give a triangular number (70500 = T₃₇₅).

The spelling of 21270288 in words is "twenty-one million, two hundred seventy thousand, two hundred eighty-eight".