21254279 has 2 divisors, whose sum is σ = 21254280. Its totient is φ = 21254278.

The previous prime is 21254273. The next prime is 21254297. The reversal of 21254279 is 97245212.

Together with next prime (21254297) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21254279 - 2⁴ = 21254263 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21254273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627139 + 10627140.

It is an arithmetic number, because the mean of its divisors is an integer number (10627140).

Almost surely, 2^21254279 is an apocalyptic number.

21254279 is a deficient number, since it is larger than the sum of its proper divisors (1).

21254279 is an equidigital number, since it uses as much as digits as its factorization.

21254279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 32.

The square root of 21254279 is about 4610.2363279988. The cubic root of 21254279 is about 277.0015031176.

The spelling of 21254279 in words is "twenty-one million, two hundred fifty-four thousand, two hundred seventy-nine".