1236042221605 has 4 divisors (see below), whose sum is σ = 1483250665932. Its totient is φ = 988833777280.

The previous prime is 1236042221569. The next prime is 1236042221629. The reversal of 1236042221605 is 5061222406321.

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 863572469796 + 372469751809 = 929286^2 + 610303^2 .

It is not a de Polignac number, because 1236042221605 - 2¹⁵ = 1236042188837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123604222156 + ... + 123604222165.

It is an arithmetic number, because the mean of its divisors is an integer number (370812666483).

Almost surely, 2^{1236042221605} is an apocalyptic number.

It is an amenable number.

1236042221605 is a deficient number, since it is larger than the sum of its proper divisors (247208444327).

1236042221605 is an equidigital number, since it uses as much as digits as its factorization.

1236042221605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247208444326.

The product of its (nonzero) digits is 34560, while the sum is 34.

Adding to 1236042221605 its reverse (5061222406321), we get a palindrome (6297264627926).

The spelling of 1236042221605 in words is "one trillion, two hundred thirty-six billion, forty-two million, two hundred twenty-one thousand, six hundred five".