1311231023205 has 64 divisors (see below), whose sum is σ = 2187624257280. Its totient is φ = 670242400256.

The previous prime is 1311231023177. The next prime is 1311231023213. The reversal of 1311231023205 is 5023201321131.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1311231023205 - 2¹⁵ = 1311230990437 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5761027 + ... + 5984303.

It is an arithmetic number, because the mean of its divisors is an integer number (34181629020).

Almost surely, 2^{1311231023205} is an apocalyptic number.

1311231023205 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1311231023205 is a deficient number, since it is larger than the sum of its proper divisors (876393234075).

1311231023205 is a wasteful number, since it uses less digits than its factorization.

1311231023205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223510.

The product of its (nonzero) digits is 1080, while the sum is 24.

Adding to 1311231023205 its reverse (5023201321131), we get a palindrome (6334432344336).

The spelling of 1311231023205 in words is "one trillion, three hundred eleven billion, two hundred thirty-one million, twenty-three thousand, two hundred five".