21367889 has 2 divisors, whose sum is σ = 21367890. Its totient is φ = 21367888.

The previous prime is 21367883. The next prime is 21367891. The reversal of 21367889 is 98876312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19360000 + 2007889 = 4400^2 + 1417^2 .

It is a cyclic number.

It is not a de Polignac number, because 21367889 - 2²⁴ = 4590673 is a prime.

Together with 21367891, 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 (21367883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10683944 + 10683945.

It is an arithmetic number, because the mean of its divisors is an integer number (10683945).

Almost surely, 2^21367889 is an apocalyptic number.

It is an amenable number.

21367889 is a deficient number, since it is larger than the sum of its proper divisors (1).

21367889 is an equidigital number, since it uses as much as digits as its factorization.

21367889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 44.

The square root of 21367889 is about 4622.5414005718. The cubic root of 21367889 is about 277.4941762163.

The spelling of 21367889 in words is "twenty-one million, three hundred sixty-seven thousand, eight hundred eighty-nine".