1306136635561 has 4 divisors (see below), whose sum is σ = 1310309596372. Its totient is φ = 1301963674752.

The previous prime is 1306136635523. The next prime is 1306136635589. The reversal of 1306136635561 is 1655366316031.

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 268551968400 + 1037584667161 = 518220^2 + 1018619^2 .

It is a cyclic number.

It is not a de Polignac number, because 1306136635561 - 2⁹ = 1306136635049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1306136695561) 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, 2086479936 + ... + 2086480561.

It is an arithmetic number, because the mean of its divisors is an integer number (327577399093).

Almost surely, 2^{1306136635561} is an apocalyptic number.

It is an amenable number.

1306136635561 is a deficient number, since it is larger than the sum of its proper divisors (4172960811).

1306136635561 is an equidigital number, since it uses as much as digits as its factorization.

1306136635561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4172960810.

The product of its (nonzero) digits is 874800, while the sum is 46.

The spelling of 1306136635561 in words is "one trillion, three hundred six billion, one hundred thirty-six million, six hundred thirty-five thousand, five hundred sixty-one".