21075128 has 16 divisors (see below), whose sum is σ = 39665760. Its totient is φ = 10497600.

The previous prime is 21075113. The next prime is 21075137. The reversal of 21075128 is 82157012.

It is a super-2 number, since 2×21075128² = 888322040432768, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21075097 and 21075106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2693 + ... + 7028.

It is an arithmetic number, because the mean of its divisors is an integer number (2479110).

Almost surely, 2^21075128 is an apocalyptic number.

It is an amenable number.

21075128 is a deficient number, since it is larger than the sum of its proper divisors (18590632).

21075128 is a wasteful number, since it uses less digits than its factorization.

21075128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9998 (or 9994 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21075128 is about 4590.7655135064. The cubic root of 21075128 is about 276.2210299739.

The spelling of 21075128 in words is "twenty-one million, seventy-five thousand, one hundred twenty-eight".