2191220 has 18 divisors (see below), whose sum is σ = 4615506. Its totient is φ = 873840.

The previous prime is 2191199. The next prime is 2191229. The reversal of 2191220 is 221912.

It can be written as a sum of positive squares in only one way, i.e., 1752976 + 438244 = 1324^2 + 662^2 .

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191229) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6455 + ... + 6785.

It is an arithmetic number, because the mean of its divisors is an integer number (256417).

2^2191220 is an apocalyptic number.

2191220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2191220 is an abundant number, since it is smaller than the sum of its proper divisors (2424286).

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

2191220 is an equidigital number, since it uses as much as digits as its factorization.

2191220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671 (or 338 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 2191220 is about 1480.2770011049. The cubic root of 2191220 is about 129.8858959327.

The spelling of 2191220 in words is "two million, one hundred ninety-one thousand, two hundred twenty".