21667123 has 2 divisors, whose sum is σ = 21667124. Its totient is φ = 21667122.

The previous prime is 21667111. The next prime is 21667153. The reversal of 21667123 is 32176612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21667123 - 2⁵ = 21667091 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21667091 and 21667100.

It is not a weakly prime, because it can be changed into another prime (21667103) 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, 10833561 + 10833562.

It is an arithmetic number, because the mean of its divisors is an integer number (10833562).

Almost surely, 2^21667123 is an apocalyptic number.

21667123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21667123 is an equidigital number, since it uses as much as digits as its factorization.

21667123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

The square root of 21667123 is about 4654.7956990613. The cubic root of 21667123 is about 278.7835107547.

The spelling of 21667123 in words is "twenty-one million, six hundred sixty-seven thousand, one hundred twenty-three".