2120878809 has 135 divisors (see below), whose sum is σ = 4008198447. Its totient is φ = 1114114176.

The previous prime is 2120878789. The next prime is 2120878847. The reversal of 2120878809 is 9088780212.

It is a happy number.

The square root of 2120878809 is 46053.

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

It can be written as a sum of positive squares in only one way, i.e., 1651203225 + 469675584 = 40635^2 + 21672^2 .

It is not a de Polignac number, because 2120878809 - 2⁵ = 2120878777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2120878849) 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 134 ways as a sum of consecutive naturals, for example, 49322742 + ... + 49322784.

Almost surely, 2^2120878809 is an apocalyptic number.

2120878809 is the 46053-rd square number.

2120878809 is the 23027-th centered octagonal number.

It is an amenable number.

2120878809 is a deficient number, since it is larger than the sum of its proper divisors (1887319638).

2120878809 is an equidigital number, since it uses as much as digits as its factorization.

2120878809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 70 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The cubic root of 2120878809 is about 1284.8091404017.

The spelling of 2120878809 in words is "two billion, one hundred twenty million, eight hundred seventy-eight thousand, eight hundred nine".