2138420209 has 4 divisors (see below), whose sum is σ = 2173476340. Its totient is φ = 2103364080.

The previous prime is 2138420197. The next prime is 2138420237. The reversal of 2138420209 is 9020248312.

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 932386225 + 1206033984 = 30535^2 + 34728^2 .

It is a cyclic number.

It is not a de Polignac number, because 2138420209 - 2¹⁷ = 2138289137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2138420279) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17527974 + ... + 17528095.

It is an arithmetic number, because the mean of its divisors is an integer number (543369085).

Almost surely, 2^2138420209 is an apocalyptic number.

It is an amenable number.

2138420209 is a deficient number, since it is larger than the sum of its proper divisors (35056131).

2138420209 is an equidigital number, since it uses as much as digits as its factorization.

2138420209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35056130.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 2138420209 is about 46243.0557921944. The cubic root of 2138420209 is about 1288.3415598866.

The spelling of 2138420209 in words is "two billion, one hundred thirty-eight million, four hundred twenty thousand, two hundred nine".