21298128 has 20 divisors (see below), whose sum is σ = 55020288. Its totient is φ = 7099360.

The previous prime is 21298117. The next prime is 21298141. The reversal of 21298128 is 82189212.

It is a super-2 number, since 2×21298128² = 907220512608768, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221808 + ... + 221903.

Almost surely, 2^21298128 is an apocalyptic number.

It is an amenable number.

21298128 is an abundant number, since it is smaller than the sum of its proper divisors (33722160).

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

21298128 is a wasteful number, since it uses less digits than its factorization.

21298128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443722 (or 443716 counting only the distinct ones).

The product of its digits is 4608, while the sum is 33.

The square root of 21298128 is about 4614.9894907789. The cubic root of 21298128 is about 277.1918631487.

The spelling of 21298128 in words is "twenty-one million, two hundred ninety-eight thousand, one hundred twenty-eight".