121810 has 16 divisors (see below), whose sum is σ = 236376. Its totient is φ = 44928.

The previous prime is 121789. The next prime is 121843. The reversal of 121810 is 18121.

It can be written as a sum of positive squares in 4 ways, for example, as 42849 + 78961 = 207^2 + 281^2 .

It is a super-2 number, since 2×121810² = 29675352200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

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

It is an unprimeable number.

121810 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 (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 339 + ... + 598.

2¹²¹⁸¹⁰ is an apocalyptic number.

121810 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121810 is a deficient number, since it is larger than the sum of its proper divisors (114566).

121810 is a wasteful number, since it uses less digits than its factorization.

121810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 121810 is about 349.0128937446. The cubic root of 121810 is about 49.5709963108.

Adding to 121810 its reverse (18121), we get a palindrome (139931).

The spelling of 121810 in words is "one hundred twenty-one thousand, eight hundred ten".