121687 has 2 divisors, whose sum is σ = 121688. Its totient is φ = 121686.

The previous prime is 121661. The next prime is 121697. The reversal of 121687 is 786121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121687 - 2⁷ = 121559 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60843 + 60844.

It is an arithmetic number, because the mean of its divisors is an integer number (60844).

2¹²¹⁶⁸⁷ is an apocalyptic number.

121687 is a deficient number, since it is larger than the sum of its proper divisors (1).

121687 is an equidigital number, since it uses as much as digits as its factorization.

121687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672, while the sum is 25.

The square root of 121687 is about 348.8366379840. The cubic root of 121687 is about 49.5543056013.

It can be divided in two parts, 121 and 687, that added together give a palindrome (808).

The spelling of 121687 in words is "one hundred twenty-one thousand, six hundred eighty-seven".