121858 has 16 divisors (see below), whose sum is σ = 207360. Its totient is φ = 53200.

The previous prime is 121853. The next prime is 121867. The reversal of 121858 is 858121.

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121853) by changing a digit.

121858 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 543 + ... + 733.

It is an arithmetic number, because the mean of its divisors is an integer number (12960).

2¹²¹⁸⁵⁸ is an apocalyptic number.

121858 is a deficient number, since it is larger than the sum of its proper divisors (85502).

121858 is a wasteful number, since it uses less digits than its factorization.

121858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233.

The product of its digits is 640, while the sum is 25.

The square root of 121858 is about 349.0816523394. The cubic root of 121858 is about 49.5775067104.

Adding to 121858 its reverse (858121), we get a palindrome (979979).

It can be divided in two parts, 121 and 858, that added together give a palindrome (979).

The spelling of 121858 in words is "one hundred twenty-one thousand, eight hundred fifty-eight".