1312261662391 has 4 divisors (see below), whose sum is σ = 1314770767432. Its totient is φ = 1309752557352.

The previous prime is 1312261662337. The next prime is 1312261662419. The reversal of 1312261662391 is 1932661622131.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1312261662391 - 2¹³ = 1312261654199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312261662331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1254551736 + ... + 1254552781.

It is an arithmetic number, because the mean of its divisors is an integer number (328692691858).

Almost surely, 2^{1312261662391} is an apocalyptic number.

1312261662391 is a deficient number, since it is larger than the sum of its proper divisors (2509105041).

1312261662391 is an equidigital number, since it uses as much as digits as its factorization.

1312261662391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2509105040.

The product of its digits is 139968, while the sum is 43.

The spelling of 1312261662391 in words is "one trillion, three hundred twelve billion, two hundred sixty-one million, six hundred sixty-two thousand, three hundred ninety-one".