21066863 has 2 divisors, whose sum is σ = 21066864. Its totient is φ = 21066862.

The previous prime is 21066841. The next prime is 21066931. The reversal of 21066863 is 36866012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21066863 - 2⁸ = 21066607 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21066823) 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, 10533431 + 10533432.

It is an arithmetic number, because the mean of its divisors is an integer number (10533432).

Almost surely, 2^21066863 is an apocalyptic number.

21066863 is a deficient number, since it is larger than the sum of its proper divisors (1).

21066863 is an equidigital number, since it uses as much as digits as its factorization.

21066863 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21066863 is about 4589.8652485667. The cubic root of 21066863 is about 276.1849168629.

The spelling of 21066863 in words is "twenty-one million, sixty-six thousand, eight hundred sixty-three".