2178873809 has 4 divisors (see below), whose sum is σ = 2490141504. Its totient is φ = 1867606116.

The previous prime is 2178873779. The next prime is 2178873821. The reversal of 2178873809 is 9083788712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2178873809 - 2⁸ = 2178873553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2178873839) 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, 155633837 + ... + 155633850.

It is an arithmetic number, because the mean of its divisors is an integer number (622535376).

Almost surely, 2^2178873809 is an apocalyptic number.

It is an amenable number.

2178873809 is a deficient number, since it is larger than the sum of its proper divisors (311267695).

2178873809 is an equidigital number, since it uses as much as digits as its factorization.

2178873809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311267694.

The product of its (nonzero) digits is 1354752, while the sum is 53.

The square root of 2178873809 is about 46678.4083811777. The cubic root of 2178873809 is about 1296.4149368113.

The spelling of 2178873809 in words is "two billion, one hundred seventy-eight million, eight hundred seventy-three thousand, eight hundred nine".