21266679 has 8 divisors (see below), whose sum is σ = 32406400. Its totient is φ = 12152376.

The previous prime is 21266669. The next prime is 21266731. The reversal of 21266679 is 97666212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21266679 - 2⁷ = 21266551 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 (21266629) 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 in 7 ways as a sum of consecutive naturals, for example, 506329 + ... + 506370.

It is an arithmetic number, because the mean of its divisors is an integer number (4050800).

Almost surely, 2^21266679 is an apocalyptic number.

21266679 is a deficient number, since it is larger than the sum of its proper divisors (11139721).

21266679 is a wasteful number, since it uses less digits than its factorization.

21266679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1012709.

The product of its digits is 54432, while the sum is 39.

The square root of 21266679 is about 4611.5809653523. The cubic root of 21266679 is about 277.0553613059.

It can be divided in two parts, 21266 and 679, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21266679 in words is "twenty-one million, two hundred sixty-six thousand, six hundred seventy-nine".