21127284 has 48 divisors (see below), whose sum is σ = 55823040. Its totient is φ = 6907680.

The previous prime is 21127273. The next prime is 21127291. The reversal of 21127284 is 48272112.

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

It is a congruent 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, 3879 + ... + 7569.

It is an arithmetic number, because the mean of its divisors is an integer number (1162980).

Almost surely, 2^21127284 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 21127284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27911520).

21127284 is an abundant number, since it is smaller than the sum of its proper divisors (34695756).

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

21127284 is a wasteful number, since it uses less digits than its factorization.

21127284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3757 (or 3749 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 21127284 is about 4596.4425374413. The cubic root of 21127284 is about 276.4487030245.

Adding to 21127284 its reverse (48272112), we get a palindrome (69399396).

It can be divided in two parts, 211 and 27284, that added together give a triangular number (27495 = T₂₃₄).

The spelling of 21127284 in words is "twenty-one million, one hundred twenty-seven thousand, two hundred eighty-four".