1311205005 has 72 divisors (see below), whose sum is σ = 2510549496. Its totient is φ = 632586240.

The previous prime is 1311204913. The next prime is 1311205061. The reversal of 1311205005 is 5005021131.

It can be written as a sum of positive squares in 4 ways, for example, as 175986756 + 1135218249 = 13266^2 + 33693^2 .

It is not a de Polignac number, because 1311205005 - 2¹² = 1311200909 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1398897 + ... + 1399833.

It is an arithmetic number, because the mean of its divisors is an integer number (34868743).

Almost surely, 2^1311205005 is an apocalyptic number.

1311205005 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1311205005 is a deficient number, since it is larger than the sum of its proper divisors (1199344491).

1311205005 is a wasteful number, since it uses less digits than its factorization.

1311205005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227 (or 1213 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 1311205005 is about 36210.5648257522. The cubic root of 1311205005 is about 1094.5195740715.

Adding to 1311205005 its reverse (5005021131), we get a palindrome (6316226136).

The spelling of 1311205005 in words is "one billion, three hundred eleven million, two hundred five thousand, five".