21164028 has 24 divisors (see below), whose sum is σ = 49865088. Its totient is φ = 6985776.

The previous prime is 21163999. The next prime is 21164029. The reversal of 21164028 is 82046112.

It is a junction number, because it is equal to n+sod(n) for n = 21163989 and 21164007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21164029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7326 + ... + 9797.

It is an arithmetic number, because the mean of its divisors is an integer number (2077712).

Almost surely, 2^21164028 is an apocalyptic number.

It is an amenable number.

21164028 is an abundant number, since it is smaller than the sum of its proper divisors (28701060).

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

21164028 is a wasteful number, since it uses less digits than its factorization.

21164028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17233 (or 17231 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21164028 is about 4600.4378052529. The cubic root of 21164028 is about 276.6088742370.

The spelling of 21164028 in words is "twenty-one million, one hundred sixty-four thousand, twenty-eight".