21125428 has 12 divisors (see below), whose sum is σ = 37002112. Its totient is φ = 10553400.

The previous prime is 21125393. The next prime is 21125443. The reversal of 21125428 is 82452112.

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, 6451 + ... + 9157.

Almost surely, 2^21125428 is an apocalyptic number.

It is an amenable number.

21125428 is a deficient number, since it is larger than the sum of its proper divisors (15876684).

21125428 is a wasteful number, since it uses less digits than its factorization.

21125428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4662 (or 4660 counting only the distinct ones).

The product of its digits is 1280, while the sum is 25.

The square root of 21125428 is about 4596.2406377386. The cubic root of 21125428 is about 276.4406075870.

The spelling of 21125428 in words is "twenty-one million, one hundred twenty-five thousand, four hundred twenty-eight".