21122028 has 18 divisors (see below), whose sum is σ = 53391884. Its totient is φ = 7040664.

The previous prime is 21122009. The next prime is 21122033. The reversal of 21122028 is 82022112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21122028² = 892280133665568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 21122028.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 293326 + ... + 293397.

Almost surely, 2^21122028 is an apocalyptic number.

It is an amenable number.

21122028 is an abundant number, since it is smaller than the sum of its proper divisors (32269856).

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

21122028 is a wasteful number, since it uses less digits than its factorization.

21122028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586733 (or 586728 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 21122028 is about 4595.8707553629. The cubic root of 21122028 is about 276.4257763531.

The spelling of 21122028 in words is "twenty-one million, one hundred twenty-two thousand, twenty-eight".