2118685840 has 40 divisors (see below), whose sum is σ = 4935150648. Its totient is φ = 845890560.

The previous prime is 2118685819. The next prime is 2118685841. The reversal of 2118685840 is 485868112.

It can be written as a sum of positive squares in 4 ways, for example, as 133448704 + 1985237136 = 11552^2 + 44556^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (2118685841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18804 + ... + 67756.

Almost surely, 2^2118685840 is an apocalyptic number.

2118685840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2118685840 is an abundant number, since it is smaller than the sum of its proper divisors (2816464808).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2118685840 is a wasteful number, since it uses less digits than its factorization.

2118685840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49507 (or 49501 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 43.

The square root of 2118685840 is about 46029.1846549556. The cubic root of 2118685840 is about 1284.3661607796.

The spelling of 2118685840 in words is "two billion, one hundred eighteen million, six hundred eighty-five thousand, eight hundred forty".