21167279 has 4 divisors (see below), whose sum is σ = 24191184. Its totient is φ = 18143376.

The previous prime is 21167257. The next prime is 21167297. The reversal of 21167279 is 97276112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21167279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21167239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1511942 + ... + 1511955.

It is an arithmetic number, because the mean of its divisors is an integer number (6047796).

Almost surely, 2^21167279 is an apocalyptic number.

21167279 is a deficient number, since it is larger than the sum of its proper divisors (3023905).

21167279 is an equidigital number, since it uses as much as digits as its factorization.

21167279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3023904.

The product of its digits is 10584, while the sum is 35.

The square root of 21167279 is about 4600.7911276214. The cubic root of 21167279 is about 276.6230367806.

The spelling of 21167279 in words is "twenty-one million, one hundred sixty-seven thousand, two hundred seventy-nine".