21079243 has 2 divisors, whose sum is σ = 21079244. Its totient is φ = 21079242.

The previous prime is 21079237. The next prime is 21079271. The reversal of 21079243 is 34297012.

It is an a-pointer prime, because the next prime (21079271) can be obtained adding 21079243 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21079243 - 2⁹ = 21078731 is a prime.

It is not a weakly prime, because it can be changed into another prime (21049243) 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 as a sum of consecutive naturals, namely, 10539621 + 10539622.

It is an arithmetic number, because the mean of its divisors is an integer number (10539622).

Almost surely, 2^21079243 is an apocalyptic number.

21079243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21079243 is an equidigital number, since it uses as much as digits as its factorization.

21079243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21079243 is about 4591.2136739647. The cubic root of 21079243 is about 276.2390065444.

The spelling of 21079243 in words is "twenty-one million, seventy-nine thousand, two hundred forty-three".