21269028 has 48 divisors (see below), whose sum is σ = 55077120. Its totient is φ = 6333600.

The previous prime is 21269009. The next prime is 21269033. The reversal of 21269028 is 82096212.

It is a junction number, because it is equal to n+sod(n) for n = 21268986 and 21269004.

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, 6423 + ... + 9153.

It is an arithmetic number, because the mean of its divisors is an integer number (1147440).

Almost surely, 2^21269028 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 21269028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27538560).

21269028 is an abundant number, since it is smaller than the sum of its proper divisors (33808092).

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

21269028 is a wasteful number, since it uses less digits than its factorization.

21269028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2808 (or 2806 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 21269028 is about 4611.8356432119. The cubic root of 21269028 is about 277.0655615991.

The spelling of 21269028 in words is "twenty-one million, two hundred sixty-nine thousand, twenty-eight".