21023279 has 2 divisors, whose sum is σ = 21023280. Its totient is φ = 21023278.

The previous prime is 21023269. The next prime is 21023287. The reversal of 21023279 is 97232012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21023279 - 2⁴ = 21023263 is a 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 (21023209) 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, 10511639 + 10511640.

It is an arithmetic number, because the mean of its divisors is an integer number (10511640).

Almost surely, 2^21023279 is an apocalyptic number.

21023279 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023279 is an equidigital number, since it uses as much as digits as its factorization.

21023279 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21023279 is about 4585.1149385811. The cubic root of 21023279 is about 275.9943244300.

The spelling of 21023279 in words is "twenty-one million, twenty-three thousand, two hundred seventy-nine".