2157220 has 24 divisors (see below), whose sum is σ = 4879224. Its totient is φ = 796416.

The previous prime is 2157209. The next prime is 2157229. The reversal of 2157220 is 227512.

It can be written as a sum of positive squares in 4 ways, for example, as 451584 + 1705636 = 672^2 + 1306^2 .

It is not an unprimeable number, because it can be changed into a prime (2157229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3889 + ... + 4408.

It is an arithmetic number, because the mean of its divisors is an integer number (203301).

2^2157220 is an apocalyptic number.

2157220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2157220 is an abundant number, since it is smaller than the sum of its proper divisors (2722004).

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

2157220 is a wasteful number, since it uses less digits than its factorization.

2157220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8319 (or 8317 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 2157220 is about 1468.7477659557. The cubic root of 2157220 is about 129.2106008485.

The spelling of 2157220 in words is "two million, one hundred fifty-seven thousand, two hundred twenty".