21166807 has 2 divisors, whose sum is σ = 21166808. Its totient is φ = 21166806.

The previous prime is 21166799. The next prime is 21166813. The reversal of 21166807 is 70866112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21166807 - 2³ = 21166799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21166837) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10583403 + 10583404.

It is an arithmetic number, because the mean of its divisors is an integer number (10583404).

Almost surely, 2^21166807 is an apocalyptic number.

21166807 is a deficient number, since it is larger than the sum of its proper divisors (1).

21166807 is an equidigital number, since it uses as much as digits as its factorization.

21166807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21166807 is about 4600.7398318097. The cubic root of 21166807 is about 276.6209806661.

The spelling of 21166807 in words is "twenty-one million, one hundred sixty-six thousand, eight hundred seven".