21028646 has 16 divisors (see below), whose sum is σ = 32356800. Its totient is φ = 10245120.

The previous prime is 21028619. The next prime is 21028661. The reversal of 21028646 is 64682012.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32486 + ... + 33126.

It is an arithmetic number, because the mean of its divisors is an integer number (2022300).

Almost surely, 2^21028646 is an apocalyptic number.

21028646 is a deficient number, since it is larger than the sum of its proper divisors (11328154).

21028646 is a wasteful number, since it uses less digits than its factorization.

21028646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1039.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 21028646 is about 4585.7001646423. The cubic root of 21028646 is about 276.0178084847.

The spelling of 21028646 in words is "twenty-one million, twenty-eight thousand, six hundred forty-six".