21189827 has 2 divisors, whose sum is σ = 21189828. Its totient is φ = 21189826.

The previous prime is 21189821. The next prime is 21189899. The reversal of 21189827 is 72898112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21189827 - 2¹⁰ = 21188803 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another 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 as a sum of consecutive naturals, namely, 10594913 + 10594914.

It is an arithmetic number, because the mean of its divisors is an integer number (10594914).

Almost surely, 2^21189827 is an apocalyptic number.

21189827 is a deficient number, since it is larger than the sum of its proper divisors (1).

21189827 is an equidigital number, since it uses as much as digits as its factorization.

21189827 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 38.

The square root of 21189827 is about 4603.2409235233. The cubic root of 21189827 is about 276.7212242208.

The spelling of 21189827 in words is "twenty-one million, one hundred eighty-nine thousand, eight hundred twenty-seven".