21489827 has 2 divisors, whose sum is σ = 21489828. Its totient is φ = 21489826.

The previous prime is 21489821. The next prime is 21489829. The reversal of 21489827 is 72898412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21489827 - 2¹² = 21485731 is a prime.

Together with 21489829, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21489821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10744913 + 10744914.

It is an arithmetic number, because the mean of its divisors is an integer number (10744914).

Almost surely, 2^21489827 is an apocalyptic number.

21489827 is a deficient number, since it is larger than the sum of its proper divisors (1).

21489827 is an equidigital number, since it uses as much as digits as its factorization.

21489827 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 41.

The square root of 21489827 is about 4635.7121351525. The cubic root of 21489827 is about 278.0210247543.

The spelling of 21489827 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred twenty-seven".