1312231720181 has 4 divisors (see below), whose sum is σ = 1312234185612. Its totient is φ = 1312229254752.

The previous prime is 1312231720171. The next prime is 1312231720183. The reversal of 1312231720181 is 1810271322131.

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 943989071281 + 368242648900 = 971591^2 + 606830^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1312231720181 is a prime.

It is a super-2 number, since 2×1312231720181² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312231720183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66686 + ... + 1621391.

It is an arithmetic number, because the mean of its divisors is an integer number (328058546403).

Almost surely, 2^{1312231720181} is an apocalyptic number.

It is an amenable number.

1312231720181 is a deficient number, since it is larger than the sum of its proper divisors (2465431).

1312231720181 is an equidigital number, since it uses as much as digits as its factorization.

1312231720181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2465430.

The product of its (nonzero) digits is 4032, while the sum is 32.

The spelling of 1312231720181 in words is "one trillion, three hundred twelve billion, two hundred thirty-one million, seven hundred twenty thousand, one hundred eighty-one".