11638578691 has 2 divisors, whose sum is σ = 11638578692. Its totient is φ = 11638578690.

The previous prime is 11638578689. The next prime is 11638578767. The reversal of 11638578691 is 19687583611.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11638578691 - 2¹ = 11638578689 is a prime.

Together with 11638578689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (11638578491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5819289345 + 5819289346.

It is an arithmetic number, because the mean of its divisors is an integer number (5819289346).

Almost surely, 2^11638578691 is an apocalyptic number.

11638578691 is a deficient number, since it is larger than the sum of its proper divisors (1).

11638578691 is an equidigital number, since it uses as much as digits as its factorization.

11638578691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 55.

The spelling of 11638578691 in words is "eleven billion, six hundred thirty-eight million, five hundred seventy-eight thousand, six hundred ninety-one".