21286673 has 2 divisors, whose sum is σ = 21286674. Its totient is φ = 21286672.

The previous prime is 21286633. The next prime is 21286691. The reversal of 21286673 is 37668212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21270544 + 16129 = 4612^2 + 127^2 .

It is a cyclic number.

It is not a de Polignac number, because 21286673 - 2⁸ = 21286417 is a prime.

It is not a weakly prime, because it can be changed into another prime (21286613) 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, 10643336 + 10643337.

It is an arithmetic number, because the mean of its divisors is an integer number (10643337).

Almost surely, 2^21286673 is an apocalyptic number.

It is an amenable number.

21286673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21286673 is an equidigital number, since it uses as much as digits as its factorization.

21286673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 35.

The square root of 21286673 is about 4613.7482592790. The cubic root of 21286673 is about 277.1421592151.

The spelling of 21286673 in words is "twenty-one million, two hundred eighty-six thousand, six hundred seventy-three".