21166679 has 2 divisors, whose sum is σ = 21166680. Its totient is φ = 21166678.

The previous prime is 21166643. The next prime is 21166711. The reversal of 21166679 is 97666112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21166679 - 2²⁰ = 20118103 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 (21166609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10583339 + 10583340.

It is an arithmetic number, because the mean of its divisors is an integer number (10583340).

Almost surely, 2^21166679 is an apocalyptic number.

21166679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21166679 is an equidigital number, since it uses as much as digits as its factorization.

21166679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 38.

The square root of 21166679 is about 4600.7259209825. The cubic root of 21166679 is about 276.6204230705.

The spelling of 21166679 in words is "twenty-one million, one hundred sixty-six thousand, six hundred seventy-nine".