21270027605 has 4 divisors (see below), whose sum is σ = 25524033132. Its totient is φ = 17016022080.

The previous prime is 21270027599. The next prime is 21270027617. The reversal of 21270027605 is 50672007212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4705822801 + 16564204804 = 68599^2 + 128702^2 .

It is not a de Polignac number, because 21270027605 - 2⁴ = 21270027589 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2127002756 + ... + 2127002765.

It is an arithmetic number, because the mean of its divisors is an integer number (6381008283).

Almost surely, 2^21270027605 is an apocalyptic number.

It is an amenable number.

21270027605 is a deficient number, since it is larger than the sum of its proper divisors (4254005527).

21270027605 is an equidigital number, since it uses as much as digits as its factorization.

21270027605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4254005526.

The product of its (nonzero) digits is 11760, while the sum is 32.

The spelling of 21270027605 in words is "twenty-one billion, two hundred seventy million, twenty-seven thousand, six hundred five".