21279307 has 12 divisors (see below), whose sum is σ = 24690160. Its totient is φ = 17963856.

The previous prime is 21279289. The next prime is 21279319. The reversal of 21279307 is 70397212.

It is not a de Polignac number, because 21279307 - 2¹⁵ = 21246539 is a prime.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21279397) 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 11 ways as a sum of consecutive naturals, for example, 127338 + ... + 127504.

Almost surely, 2^21279307 is an apocalyptic number.

21279307 is a deficient number, since it is larger than the sum of its proper divisors (3410853).

21279307 is an equidigital number, since it uses as much as digits as its factorization.

21279307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450 (or 283 counting only the distinct ones).

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 21279307 is about 4612.9499238557. The cubic root of 21279307 is about 277.1101882778.

The spelling of 21279307 in words is "twenty-one million, two hundred seventy-nine thousand, three hundred seven".