12820827521 has 4 divisors (see below), whose sum is σ = 12821316612. Its totient is φ = 12820338432.

The previous prime is 12820827517. The next prime is 12820827533. The reversal of 12820827521 is 12572802821.

12820827521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12572802821 = 47 ⋅267506443.

It can be written as a sum of positive squares in 2 ways, for example, as 7141095025 + 5679732496 = 84505^2 + 75364^2 .

It is a cyclic number.

It is not a de Polignac number, because 12820827521 - 2² = 12820827517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12820827541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202856 + ... + 258441.

It is an arithmetic number, because the mean of its divisors is an integer number (3205329153).

Almost surely, 2^12820827521 is an apocalyptic number.

It is an amenable number.

12820827521 is a deficient number, since it is larger than the sum of its proper divisors (489091).

12820827521 is an equidigital number, since it uses as much as digits as its factorization.

12820827521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489090.

The product of its (nonzero) digits is 35840, while the sum is 38.

The spelling of 12820827521 in words is "twelve billion, eight hundred twenty million, eight hundred twenty-seven thousand, five hundred twenty-one".