2155680 has 96 divisors (see below), whose sum is σ = 7560000. Its totient is φ = 573696.

The previous prime is 2155667. The next prime is 2155691. The reversal of 2155680 is 865512.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4071 + ... + 4569.

It is an arithmetic number, because the mean of its divisors is an integer number (78750).

2^2155680 is an apocalyptic number.

2155680 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 2155680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3780000).

2155680 is an abundant number, since it is smaller than the sum of its proper divisors (5404320).

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

2155680 is a wasteful number, since it uses less digits than its factorization.

2155680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 2155680 is about 1468.2234162415. The cubic root of 2155680 is about 129.1798464988.

The spelling of 2155680 in words is "two million, one hundred fifty-five thousand, six hundred eighty".