221810 has 16 divisors (see below), whose sum is σ = 409752. Its totient is φ = 86400.

The previous prime is 221807. The next prime is 221813. The reversal of 221810 is 18122.

221810 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (221807) and next prime (221813).

It can be written as a sum of positive squares in 4 ways, for example, as 108241 + 113569 = 329^2 + 337^2 .

It is a super-2 number, since 2×221810² = 98399352200, which contains 22 as substring.

It is an Ulam number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (221813) 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, 140 + ... + 680.

2²²¹⁸¹⁰ is an apocalyptic number.

221810 is a deficient number, since it is larger than the sum of its proper divisors (187942).

221810 is a wasteful number, since it uses less digits than its factorization.

221810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 221810 is about 470.9670901454. The cubic root of 221810 is about 60.5332103710.

Adding to 221810 its reverse (18122), we get a palindrome (239932).

It can be divided in two parts, 2 and 21810, that added together give a palindrome (21812).

The spelling of 221810 in words is "two hundred twenty-one thousand, eight hundred ten".