21906263 has 2 divisors, whose sum is σ = 21906264. Its totient is φ = 21906262.

The previous prime is 21906233. The next prime is 21906289. The reversal of 21906263 is 36260912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21906263 - 2⁸ = 21906007 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 (21906233) 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, 10953131 + 10953132.

It is an arithmetic number, because the mean of its divisors is an integer number (10953132).

Almost surely, 2^21906263 is an apocalyptic number.

21906263 is a deficient number, since it is larger than the sum of its proper divisors (1).

21906263 is an equidigital number, since it uses as much as digits as its factorization.

21906263 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 21906263 is about 4680.4126954789. The cubic root of 21906263 is about 279.8054047569.

The spelling of 21906263 in words is "twenty-one million, nine hundred six thousand, two hundred sixty-three".