2156784 has 80 divisors (see below), whose sum is σ = 6547200. Its totient is φ = 611520.

The previous prime is 2156761. The next prime is 2156789. The reversal of 2156784 is 4876512.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156789) 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, 16399 + ... + 16529.

It is an arithmetic number, because the mean of its divisors is an integer number (81840).

2^2156784 is an apocalyptic number.

2156784 is a gapful number since it is divisible by the number (24) 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 2156784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3273600).

2156784 is an abundant number, since it is smaller than the sum of its proper divisors (4390416).

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

2156784 is a wasteful number, since it uses less digits than its factorization.

2156784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163 (or 143 counting only the distinct ones).

The product of its digits is 13440, while the sum is 33.

The square root of 2156784 is about 1468.5993326977. The cubic root of 2156784 is about 129.2018952586.

It can be divided in two parts, 21 and 56784, that multiplied together give a square (1192464 = 1092²).

The spelling of 2156784 in words is "two million, one hundred fifty-six thousand, seven hundred eighty-four".