121987 has 4 divisors (see below), whose sum is σ = 122800. Its totient is φ = 121176.

The previous prime is 121967. The next prime is 121993. The reversal of 121987 is 789121.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121937) 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, 108 + ... + 505.

It is an arithmetic number, because the mean of its divisors is an integer number (30700).

2¹²¹⁹⁸⁷ is an apocalyptic number.

121987 is a deficient number, since it is larger than the sum of its proper divisors (813).

121987 is an equidigital number, since it uses as much as digits as its factorization.

121987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 812.

The product of its digits is 1008, while the sum is 28.

The square root of 121987 is about 349.2663739898. The cubic root of 121987 is about 49.5949949424.

The spelling of 121987 in words is "one hundred twenty-one thousand, nine hundred eighty-seven".