66121 has 4 divisors (see below), whose sum is σ = 72144. Its totient is φ = 60100.

The previous prime is 66109. The next prime is 66137. The reversal of 66121 is 12166.

66121 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.

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.

It is a cyclic number.

It is not a de Polignac number, because 66121 - 2⁵ = 66089 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66095 and 66104.

It is not an unprimeable number, because it can be changed into a prime (66161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2995 + ... + 3016.

It is an arithmetic number, because the mean of its divisors is an integer number (18036).

2⁶⁶¹²¹ is an apocalyptic number.

It is an amenable number.

66121 is a deficient number, since it is larger than the sum of its proper divisors (6023).

66121 is a wasteful number, since it uses less digits than its factorization.

66121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6022.

The product of its digits is 72, while the sum is 16.

The square root of 66121 is about 257.1400396671. The cubic root of 66121 is about 40.4370815961.

Subtracting from 66121 its product of digits (72), we obtain a square (66049 = 257²).

Adding to 66121 its reverse (12166), we get a palindrome (78287).

The spelling of 66121 in words is "sixty-six thousand, one hundred twenty-one".