21279667 has 8 divisors (see below), whose sum is σ = 21749600. Its totient is φ = 20813760.

The previous prime is 21279653. The next prime is 21279679. The reversal of 21279667 is 76697212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21279667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21279637) 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 7 ways as a sum of consecutive naturals, for example, 11263 + ... + 13015.

It is an arithmetic number, because the mean of its divisors is an integer number (2718700).

Almost surely, 2^21279667 is an apocalyptic number.

21279667 is a deficient number, since it is larger than the sum of its proper divisors (469933).

21279667 is a wasteful number, since it uses less digits than its factorization.

21279667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2013.

The product of its digits is 63504, while the sum is 40.

The square root of 21279667 is about 4612.9889442746. The cubic root of 21279667 is about 277.1117509714. Note that the first 3 decimals are identical.

The spelling of 21279667 in words is "twenty-one million, two hundred seventy-nine thousand, six hundred sixty-seven".