21281479 has 2 divisors, whose sum is σ = 21281480. Its totient is φ = 21281478.

The previous prime is 21281453. The next prime is 21281503. The reversal of 21281479 is 97418212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21281479 - 2¹¹ = 21279431 is a prime.

It is a congruent number.

It is a weakly prime.

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 as a sum of consecutive naturals, namely, 10640739 + 10640740.

It is an arithmetic number, because the mean of its divisors is an integer number (10640740).

Almost surely, 2^21281479 is an apocalyptic number.

21281479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21281479 is an equidigital number, since it uses as much as digits as its factorization.

21281479 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 34.

The square root of 21281479 is about 4613.1853420386. The cubic root of 21281479 is about 277.1196162611.

The spelling of 21281479 in words is "twenty-one million, two hundred eighty-one thousand, four hundred seventy-nine".