21164229 has 24 divisors (see below), whose sum is σ = 31917600. Its totient is φ = 13497120.

The previous prime is 21164189. The next prime is 21164237. The reversal of 21164229 is 92246112.

21164229 is a `hidden beast` number, since 2 + 11 + 642 + 2 + 9 = 666.

It is not a de Polignac number, because 21164229 - 2²⁰ = 20115653 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21164239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33882 + ... + 34500.

It is an arithmetic number, because the mean of its divisors is an integer number (1329900).

Almost surely, 2^21164229 is an apocalyptic number.

21164229 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21164229 is a deficient number, since it is larger than the sum of its proper divisors (10753371).

21164229 is a wasteful number, since it uses less digits than its factorization.

21164229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785 (or 782 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 21164229 is about 4600.4596509479. The cubic root of 21164229 is about 276.6097499085.

The spelling of 21164229 in words is "twenty-one million, one hundred sixty-four thousand, two hundred twenty-nine".