121861 has 4 divisors (see below), whose sum is σ = 125824. Its totient is φ = 117900.

The previous prime is 121853. The next prime is 121867. The reversal of 121861 is 168121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 168121 = 89 ⋅1889.

It is a cyclic number.

It is not a de Polignac number, because 121861 - 2³ = 121853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1935 + ... + 1996.

It is an arithmetic number, because the mean of its divisors is an integer number (31456).

2¹²¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

121861 is a deficient number, since it is larger than the sum of its proper divisors (3963).

121861 is an equidigital number, since it uses as much as digits as its factorization.

121861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3962.

The product of its digits is 96, while the sum is 19.

The square root of 121861 is about 349.0859493019. The cubic root of 121861 is about 49.5779135537.

Adding to 121861 its reverse (168121), we get a palindrome (289982).

The spelling of 121861 in words is "one hundred twenty-one thousand, eight hundred sixty-one".