2064138721 has 4 divisors (see below), whose sum is σ = 2119926292. Its totient is φ = 2008351152.

The previous prime is 2064138697. The next prime is 2064138733. The reversal of 2064138721 is 1278314602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1278314602 = 2 ⋅639157301.

It can be written as a sum of positive squares in 2 ways, for example, as 1464133696 + 600005025 = 38264^2 + 24495^2 .

It is a cyclic number.

It is not a de Polignac number, because 2064138721 - 2²⁹ = 1527267809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2064138821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27893730 + ... + 27893803.

It is an arithmetic number, because the mean of its divisors is an integer number (529981573).

Almost surely, 2^2064138721 is an apocalyptic number.

It is an amenable number.

2064138721 is a deficient number, since it is larger than the sum of its proper divisors (55787571).

2064138721 is an equidigital number, since it uses as much as digits as its factorization.

2064138721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55787570.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 2064138721 is about 45432.7934536277. The cubic root of 2064138721 is about 1273.2478757114.

The spelling of 2064138721 in words is "two billion, sixty-four million, one hundred thirty-eight thousand, seven hundred twenty-one".