21111128 has 16 divisors (see below), whose sum is σ = 41667000. Its totient is φ = 9999936.

The previous prime is 21111113. The next prime is 21111143. The reversal of 21111128 is 82111112.

It is an interprime number because it is at equal distance from previous prime (21111113) and next prime (21111143).

It is a nude number because it is divisible by every one of its digits.

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, 69293 + ... + 69596.

Almost surely, 2^21111128 is an apocalyptic number.

It is an amenable number.

21111128 is a deficient number, since it is larger than the sum of its proper divisors (20555872).

21111128 is a wasteful number, since it uses less digits than its factorization.

21111128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138914 (or 138910 counting only the distinct ones).

The product of its digits is 32, while the sum is 17.

The square root of 21111128 is about 4594.6847552362. The cubic root of 21111128 is about 276.3782184291.

The spelling of 21111128 in words is "twenty-one million, one hundred eleven thousand, one hundred twenty-eight".