20078039809 has 3 divisors (see below), whose sum is σ = 20078181507. Its totient is φ = 20077898112.

The previous prime is 20078039783. The next prime is 20078039851. The reversal of 20078039809 is 90893087002.

The square root of 20078039809 is 141697.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 10963137025 + 9114902784 = 104705^2 + 95472^2 .

It is not a de Polignac number, because 20078039809 - 2⁵ = 20078039777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20078039869) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 70849 + ... + 212545.

It is an arithmetic number, because the mean of its divisors is an integer number (6692727169).

Almost surely, 2^20078039809 is an apocalyptic number.

20078039809 is the 141697-th square number.

20078039809 is the 70849-th centered octagonal number.

It is an amenable number.

20078039809 is a deficient number, since it is larger than the sum of its proper divisors (141698).

20078039809 is an frugal number, since it uses more digits than its factorization.

20078039809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283394 (or 141697 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 46.

The spelling of 20078039809 in words is "twenty billion, seventy-eight million, thirty-nine thousand, eight hundred nine".