121831 has 4 divisors (see below), whose sum is σ = 127152. Its totient is φ = 116512.

The previous prime is 121789. The next prime is 121843. The reversal of 121831 is 138121.

121831 = 3² + 4² + ... + 71².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 138121 = 37 ⋅3733.

It is a cyclic number.

It is not a de Polignac number, because 121831 - 2¹¹ = 119783 is a prime.

It is a super-2 number, since 2×121831² = 29685585122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

121831 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2626 + ... + 2671.

It is an arithmetic number, because the mean of its divisors is an integer number (31788).

2¹²¹⁸³¹ is an apocalyptic number.

121831 is a deficient number, since it is larger than the sum of its proper divisors (5321).

121831 is an equidigital number, since it uses as much as digits as its factorization.

121831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5320.

The product of its digits is 48, while the sum is 16.

The square root of 121831 is about 349.0429772965. The cubic root of 121831 is about 49.5738448210.

Adding to 121831 its reverse (138121), we get a palindrome (259952).

Subtracting 121831 from its reverse (138121), we obtain a triangular number (16290 = T₁₈₀).

The spelling of 121831 in words is "one hundred twenty-one thousand, eight hundred thirty-one".