660012121 has 4 divisors (see below), whose sum is σ = 662894500. Its totient is φ = 657129744.

The previous prime is 660012079. The next prime is 660012149. The reversal of 660012121 is 121210066.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 368832025 + 291180096 = 19205^2 + 17064^2 .

It is a cyclic number.

It is not a de Polignac number, because 660012121 - 2⁷ = 660011993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660012161) 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, 1440846 + ... + 1441303.

It is an arithmetic number, because the mean of its divisors is an integer number (165723625).

Almost surely, 2^660012121 is an apocalyptic number.

It is an amenable number.

660012121 is a deficient number, since it is larger than the sum of its proper divisors (2882379).

660012121 is a wasteful number, since it uses less digits than its factorization.

660012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2882378.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 660012121 is about 25690.7010608897. The cubic root of 660012121 is about 870.6640990115.

Adding to 660012121 its reverse (121210066), we get a palindrome (781222187).

It can be divided in two parts, 6600 and 12121, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 660012121 in words is "six hundred sixty million, twelve thousand, one hundred twenty-one".