21680167 has 2 divisors, whose sum is σ = 21680168. Its totient is φ = 21680166.

The previous prime is 21680149. The next prime is 21680171. The reversal of 21680167 is 76108612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21680167 is a prime.

It is a super-2 number, since 2×21680167² = 940059282295778, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21680177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10840083 + 10840084.

It is an arithmetic number, because the mean of its divisors is an integer number (10840084).

Almost surely, 2^21680167 is an apocalyptic number.

21680167 is a deficient number, since it is larger than the sum of its proper divisors (1).

21680167 is an equidigital number, since it uses as much as digits as its factorization.

21680167 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 21680167 is about 4656.1966238551. The cubic root of 21680167 is about 278.8394437708.

Adding to 21680167 its reverse (76108612), we get a palindrome (97788779).

The spelling of 21680167 in words is "twenty-one million, six hundred eighty thousand, one hundred sixty-seven".