21168479 has 2 divisors, whose sum is σ = 21168480. Its totient is φ = 21168478.

The previous prime is 21168461. The next prime is 21168481. The reversal of 21168479 is 97486112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21168479 - 2²⁰ = 20119903 is a prime.

Together with 21168481, 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 (21168409) 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, 10584239 + 10584240.

It is an arithmetic number, because the mean of its divisors is an integer number (10584240).

Almost surely, 2^21168479 is an apocalyptic number.

21168479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21168479 is an equidigital number, since it uses as much as digits as its factorization.

21168479 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 38.

The square root of 21168479 is about 4600.9215381269. The cubic root of 21168479 is about 276.6282640525.

The spelling of 21168479 in words is "twenty-one million, one hundred sixty-eight thousand, four hundred seventy-nine".