21365229 has 16 divisors (see below), whose sum is σ = 29836800. Its totient is φ = 13573296.

The previous prime is 21365221. The next prime is 21365233. The reversal of 21365229 is 92256312.

It is not a de Polignac number, because 21365229 - 2³ = 21365221 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21365196 and 21365205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365221) 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 15 ways as a sum of consecutive naturals, for example, 28542 + ... + 29280.

It is an arithmetic number, because the mean of its divisors is an integer number (1864800).

Almost surely, 2^21365229 is an apocalyptic number.

It is an amenable number.

21365229 is a deficient number, since it is larger than the sum of its proper divisors (8471571).

21365229 is a wasteful number, since it uses less digits than its factorization.

21365229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1184.

The product of its digits is 6480, while the sum is 30.

The square root of 21365229 is about 4622.2536711003. The cubic root of 21365229 is about 277.4826610382.

The spelling of 21365229 in words is "twenty-one million, three hundred sixty-five thousand, two hundred twenty-nine".