1312688661 has 4 divisors (see below), whose sum is σ = 1750251552. Its totient is φ = 875125772.

The previous prime is 1312688651. The next prime is 1312688717. The reversal of 1312688661 is 1668862131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1312688661 - 2²¹ = 1310591509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312688651) 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, 218781441 + ... + 218781446.

It is an arithmetic number, because the mean of its divisors is an integer number (437562888).

Almost surely, 2^1312688661 is an apocalyptic number.

It is an amenable number.

1312688661 is a deficient number, since it is larger than the sum of its proper divisors (437562891).

1312688661 is an equidigital number, since it uses as much as digits as its factorization.

1312688661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437562890.

The product of its digits is 82944, while the sum is 42.

The square root of 1312688661 is about 36231.0455410826. The cubic root of 1312688661 is about 1094.9322424244.

It can be divided in two parts, 1312688 and 661, that multiplied together give a palindrome (867686768).

The spelling of 1312688661 in words is "one billion, three hundred twelve million, six hundred eighty-eight thousand, six hundred sixty-one".