21187167 has 12 divisors (see below), whose sum is σ = 29194200. Its totient is φ = 13667280.

The previous prime is 21187129. The next prime is 21187189. The reversal of 21187167 is 76178112.

It is not a de Polignac number, because 21187167 - 2⁸ = 21186911 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21187567) 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 in 11 ways as a sum of consecutive naturals, for example, 792 + ... + 6557.

It is an arithmetic number, because the mean of its divisors is an integer number (2432850).

Almost surely, 2^21187167 is an apocalyptic number.

21187167 is a deficient number, since it is larger than the sum of its proper divisors (8007033).

21187167 is an equidigital number, since it uses as much as digits as its factorization.

21187167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7414 (or 7383 counting only the distinct ones).

The product of its digits is 4704, while the sum is 33.

The square root of 21187167 is about 4602.9519875836. The cubic root of 21187167 is about 276.7096446193.

It can be divided in two parts, 211 and 87167, that added together give a palindrome (87378).

The spelling of 21187167 in words is "twenty-one million, one hundred eighty-seven thousand, one hundred sixty-seven".