2181220 has 24 divisors (see below), whose sum is σ = 4612608. Its totient is φ = 866400.

The previous prime is 2181217. The next prime is 2181227. The reversal of 2181220 is 221812.

2181220 = T₄₅₇ + T₄₅₈ + ... + T₄₇₆.

It is a junction number, because it is equal to n+sod(n) for n = 2181194 and 2181203.

It is not an unprimeable number, because it can be changed into a prime (2181227) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 3535 + ... + 4105.

It is an arithmetic number, because the mean of its divisors is an integer number (192192).

2^2181220 is an apocalyptic number.

2181220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2181220 is an abundant number, since it is smaller than the sum of its proper divisors (2431388).

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

2181220 is a wasteful number, since it uses less digits than its factorization.

2181220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771 (or 769 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 2181220 is about 1476.8953923687. The cubic root of 2181220 is about 129.6880092398.

It can be divided in two parts, 2181 and 220, that added together give a 4-th power (2401 = 7⁴).

The spelling of 2181220 in words is "two million, one hundred eighty-one thousand, two hundred twenty".