21921167 has 2 divisors, whose sum is σ = 21921168. Its totient is φ = 21921166.

The previous prime is 21921121. The next prime is 21921169. The reversal of 21921167 is 76112912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21921167 - 2⁸ = 21920911 is a prime.

Together with 21921169, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21921169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10960583 + 10960584.

It is an arithmetic number, because the mean of its divisors is an integer number (10960584).

Almost surely, 2^21921167 is an apocalyptic number.

21921167 is a deficient number, since it is larger than the sum of its proper divisors (1).

21921167 is an equidigital number, since it uses as much as digits as its factorization.

21921167 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 29.

The square root of 21921167 is about 4682.0045920524. The cubic root of 21921167 is about 279.8688458889.

The spelling of 21921167 in words is "twenty-one million, nine hundred twenty-one thousand, one hundred sixty-seven".