21164329 has 4 divisors (see below), whose sum is σ = 21202884. Its totient is φ = 21125776.

The previous prime is 21164327. The next prime is 21164357. The reversal of 21164329 is 92346112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11696400 + 9467929 = 3420^2 + 3077^2 .

It is a cyclic number.

It is not a de Polignac number, because 21164329 - 2¹ = 21164327 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21164297 and 21164306.

It is not an unprimeable number, because it can be changed into a prime (21164321) 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 3 ways as a sum of consecutive naturals, for example, 18442 + ... + 19555.

It is an arithmetic number, because the mean of its divisors is an integer number (5300721).

Almost surely, 2^21164329 is an apocalyptic number.

It is an amenable number.

21164329 is a deficient number, since it is larger than the sum of its proper divisors (38555).

21164329 is an equidigital number, since it uses as much as digits as its factorization.

21164329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38554.

The product of its digits is 2592, while the sum is 28.

The square root of 21164329 is about 4600.4705194143. The cubic root of 21164329 is about 276.6101855638.

The spelling of 21164329 in words is "twenty-one million, one hundred sixty-four thousand, three hundred twenty-nine".