21286999 has 2 divisors, whose sum is σ = 21287000. Its totient is φ = 21286998.

The previous prime is 21286981. The next prime is 21287027. The reversal of 21286999 is 99968212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21286999 - 2⁷ = 21286871 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21286919) 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, 10643499 + 10643500.

It is an arithmetic number, because the mean of its divisors is an integer number (10643500).

Almost surely, 2^21286999 is an apocalyptic number.

21286999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21286999 is an equidigital number, since it uses as much as digits as its factorization.

21286999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 46.

The square root of 21286999 is about 4613.7835883361. The cubic root of 21286999 is about 277.1435739952.

The spelling of 21286999 in words is "twenty-one million, two hundred eighty-six thousand, nine hundred ninety-nine".