21167149 has 2 divisors, whose sum is σ = 21167150. Its totient is φ = 21167148.

The previous prime is 21167147. The next prime is 21167161. The reversal of 21167149 is 94176112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20187049 + 980100 = 4493^2 + 990^2 .

It is a cyclic number.

It is not a de Polignac number, because 21167149 - 2¹ = 21167147 is a prime.

Together with 21167147, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21167149.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21167143) 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, 10583574 + 10583575.

It is an arithmetic number, because the mean of its divisors is an integer number (10583575).

Almost surely, 2^21167149 is an apocalyptic number.

It is an amenable number.

21167149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21167149 is an equidigital number, since it uses as much as digits as its factorization.

21167149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 31.

The square root of 21167149 is about 4600.7769995947. The cubic root of 21167149 is about 276.6224704809.

It can be divided in two parts, 21167 and 149, that added together give a square (21316 = 146²).

The spelling of 21167149 in words is "twenty-one million, one hundred sixty-seven thousand, one hundred forty-nine".