221690 has 16 divisors (see below), whose sum is σ = 456192. Its totient is φ = 75984.

The previous prime is 221677. The next prime is 221707. The reversal of 221690 is 96122.

It is a super-2 number, since 2×221690² = 98292912200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1514 + ... + 1653.

It is an arithmetic number, because the mean of its divisors is an integer number (28512).

2²²¹⁶⁹⁰ is an apocalyptic number.

221690 is an abundant number, since it is smaller than the sum of its proper divisors (234502).

It is a weird number, because it is abundant, but not a pseudoperfect number.

221690 is a wasteful number, since it uses less digits than its factorization.

221690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3181.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 221690 is about 470.8396754735. The cubic root of 221690 is about 60.5222921744.

The spelling of 221690 in words is "two hundred twenty-one thousand, six hundred ninety".