21026928 has 80 divisors (see below), whose sum is σ = 60440576. Its totient is φ = 6255360.

The previous prime is 21026917. The next prime is 21026933. The reversal of 21026928 is 82962012.

It is a super-2 number, since 2×21026928² = 884263402234368, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21026895 and 21026904.

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, 18801 + ... + 19887.

Almost surely, 2^21026928 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 21026928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30220288).

21026928 is an abundant number, since it is smaller than the sum of its proper divisors (39413648).

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

21026928 is a wasteful number, since it uses less digits than its factorization.

21026928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1142 (or 1136 counting only the distinct ones).

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

The square root of 21026928 is about 4585.5128393670. The cubic root of 21026928 is about 276.0102915717.

The spelling of 21026928 in words is "twenty-one million, twenty-six thousand, nine hundred twenty-eight".