21605028208711 has 2 divisors, whose sum is σ = 21605028208712. Its totient is φ = 21605028208710.

The previous prime is 21605028208691. The next prime is 21605028208817. The reversal of 21605028208711 is 11780282050612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21605028208711 - 2⁷ = 21605028208583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21605028248711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802514104355 + 10802514104356.

It is an arithmetic number, because the mean of its divisors is an integer number (10802514104356).

Almost surely, 2^{21605028208711} is an apocalyptic number.

21605028208711 is a deficient number, since it is larger than the sum of its proper divisors (1).

21605028208711 is an equidigital number, since it uses as much as digits as its factorization.

21605028208711 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 107520, while the sum is 43.

The spelling of 21605028208711 in words is "twenty-one trillion, six hundred five billion, twenty-eight million, two hundred eight thousand, seven hundred eleven".