2165680 has 80 divisors (see below), whose sum is σ = 5785344. Its totient is φ = 746240.

The previous prime is 2165671. The next prime is 2165687. The reversal of 2165680 is 865612.

2165680 = 240² + 241² + ... + 272².

It is a tau number, because it is divible by the number of its divisors (80).

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (2165687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20187 + ... + 20293.

2^2165680 is an apocalyptic number.

2165680 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 2165680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2892672).

2165680 is an abundant number, since it is smaller than the sum of its proper divisors (3619664).

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

2165680 is a wasteful number, since it uses less digits than its factorization.

2165680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 2165680 is about 1471.6249522212. The cubic root of 2165680 is about 129.3792895339.

It can be divided in two parts, 21656 and 80, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 2165680 in words is "two million, one hundred sixty-five thousand, six hundred eighty".