2161810778 has 16 divisors (see below), whose sum is σ = 3317673600. Its totient is φ = 1056002496.

The previous prime is 2161810727. The next prime is 2161810789. The reversal of 2161810778 is 8770181612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32498 + ... + 73346.

It is an arithmetic number, because the mean of its divisors is an integer number (207354600).

Almost surely, 2^2161810778 is an apocalyptic number.

2161810778 is a deficient number, since it is larger than the sum of its proper divisors (1155862822).

2161810778 is a wasteful number, since it uses less digits than its factorization.

2161810778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41461.

The product of its (nonzero) digits is 37632, while the sum is 41.

The square root of 2161810778 is about 46495.2769429326. The cubic root of 2161810778 is about 1293.0219356201.

The spelling of 2161810778 in words is "two billion, one hundred sixty-one million, eight hundred ten thousand, seven hundred seventy-eight".