2161688040 has 256 divisors, whose sum is σ = 7674912000. Its totient is φ = 539320320.

The previous prime is 2161688029. The next prime is 2161688041. The reversal of 2161688040 is 408861612.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 2161687986 and 2161688004.

It is not an unprimeable number, because it can be changed into a prime (2161688041) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5158951 + ... + 5159369.

It is an arithmetic number, because the mean of its divisors is an integer number (29980125).

Almost surely, 2^2161688040 is an apocalyptic number.

2161688040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2161688040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3837456000).

2161688040 is an abundant number, since it is smaller than the sum of its proper divisors (5513223960).

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

2161688040 is a wasteful number, since it uses less digits than its factorization.

2161688040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737 (or 727 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 2161688040 is about 46493.9570266933. The cubic root of 2161688040 is about 1292.9974644790.

The spelling of 2161688040 in words is "two billion, one hundred sixty-one million, six hundred eighty-eight thousand, forty".