1212660126721 has 4 divisors (see below), whose sum is σ = 1212701084500. Its totient is φ = 1212619168944.

The previous prime is 1212660126679. The next prime is 1212660126739. The reversal of 1212660126721 is 1276210662121.

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 1116327486096 + 96332640625 = 1056564^2 + 310375^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212660126721 - 2¹¹ = 1212660124673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1212660129721) 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, 20434446 + ... + 20493703.

It is an arithmetic number, because the mean of its divisors is an integer number (303175271125).

Almost surely, 2^{1212660126721} is an apocalyptic number.

It is an amenable number.

1212660126721 is a deficient number, since it is larger than the sum of its proper divisors (40957779).

1212660126721 is an equidigital number, since it uses as much as digits as its factorization.

1212660126721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40957778.

The product of its (nonzero) digits is 24192, while the sum is 37.

Adding to 1212660126721 its reverse (1276210662121), we get a palindrome (2488870788842).

The spelling of 1212660126721 in words is "one trillion, two hundred twelve billion, six hundred sixty million, one hundred twenty-six thousand, seven hundred twenty-one".