21189829 has 4 divisors (see below), whose sum is σ = 21200320. Its totient is φ = 21179340.

The previous prime is 21189827. The next prime is 21189899. The reversal of 21189829 is 92898112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21189829 - 2¹ = 21189827 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21189791 and 21189800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21189821) 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, 1149 + ... + 6610.

It is an arithmetic number, because the mean of its divisors is an integer number (5300080).

Almost surely, 2^21189829 is an apocalyptic number.

It is an amenable number.

21189829 is a deficient number, since it is larger than the sum of its proper divisors (10491).

21189829 is an equidigital number, since it uses as much as digits as its factorization.

21189829 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10490.

The product of its digits is 20736, while the sum is 40.

The square root of 21189829 is about 4603.2411407616. The cubic root of 21189829 is about 276.7212329269.

The spelling of 21189829 in words is "twenty-one million, one hundred eighty-nine thousand, eight hundred twenty-nine".