1231345305 has 24 divisors (see below), whose sum is σ = 2135248128. Its totient is φ = 656435616.

The previous prime is 1231345303. The next prime is 1231345321. The reversal of 1231345305 is 5035431321.

1231345305 is a `hidden beast` number, since 1 + 2 + 313 + 45 + 305 = 666.

It is not a de Polignac number, because 1231345305 - 2¹ = 1231345303 is a prime.

It is a super-2 number, since 2×1231345305² = 3032422520291086050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1231345301) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 139864 + ... + 148406.

It is an arithmetic number, because the mean of its divisors is an integer number (88968672).

Almost surely, 2^1231345305 is an apocalyptic number.

1231345305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1231345305 is a deficient number, since it is larger than the sum of its proper divisors (903902823).

1231345305 is a wasteful number, since it uses less digits than its factorization.

1231345305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11757 (or 11754 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 27.

The square root of 1231345305 is about 35090.5301327865. The cubic root of 1231345305 is about 1071.8317548136.

Adding to 1231345305 its reverse (5035431321), we get a palindrome (6266776626).

The spelling of 1231345305 in words is "one billion, two hundred thirty-one million, three hundred forty-five thousand, three hundred five".