21079567 has 2 divisors, whose sum is σ = 21079568. Its totient is φ = 21079566.

The previous prime is 21079537. The next prime is 21079621. The reversal of 21079567 is 76597012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21079567 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21079537) 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, 10539783 + 10539784.

It is an arithmetic number, because the mean of its divisors is an integer number (10539784).

Almost surely, 2^21079567 is an apocalyptic number.

21079567 is a deficient number, since it is larger than the sum of its proper divisors (1).

21079567 is an equidigital number, since it uses as much as digits as its factorization.

21079567 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26460, while the sum is 37.

The square root of 21079567 is about 4591.2489586168. The cubic root of 21079567 is about 276.2404218542.

The spelling of 21079567 in words is "twenty-one million, seventy-nine thousand, five hundred sixty-seven".