221858 has 32 divisors (see below), whose sum is σ = 435456. Its totient is φ = 82368.

The previous prime is 221849. The next prime is 221873. The reversal of 221858 is 858122.

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221858.

It is an unprimeable number.

221858 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4160 + ... + 4212.

It is an arithmetic number, because the mean of its divisors is an integer number (13608).

2²²¹⁸⁵⁸ is an apocalyptic number.

221858 is a deficient number, since it is larger than the sum of its proper divisors (213598).

221858 is a wasteful number, since it uses less digits than its factorization.

221858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98.

The product of its digits is 1280, while the sum is 26.

The square root of 221858 is about 471.0180463634. The cubic root of 221858 is about 60.5375765471.

The spelling of 221858 in words is "two hundred twenty-one thousand, eight hundred fifty-eight".