2166205678 has 16 divisors (see below), whose sum is σ = 3999149280. Its totient is φ = 856960416.

The previous prime is 2166205673. The next prime is 2166205687. The reversal of 2166205678 is 8765026612.

2166205678 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166205673) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5950933 + ... + 5951296.

It is an arithmetic number, because the mean of its divisors is an integer number (249946830).

Almost surely, 2^2166205678 is an apocalyptic number.

2166205678 is a deficient number, since it is larger than the sum of its proper divisors (1832943602).

2166205678 is a wasteful number, since it uses less digits than its factorization.

2166205678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11902251.

The product of its (nonzero) digits is 241920, while the sum is 43.

The square root of 2166205678 is about 46542.5147365288. The cubic root of 2166205678 is about 1293.8975681503.

The spelling of 2166205678 in words is "two billion, one hundred sixty-six million, two hundred five thousand, six hundred seventy-eight".