11535621991 has 2 divisors, whose sum is σ = 11535621992. Its totient is φ = 11535621990.

The previous prime is 11535621971. The next prime is 11535622013. The reversal of 11535621991 is 19912653511.

It is a weak prime.

It is an emirp because it is prime and its reverse (19912653511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11535621991 - 2⁵ = 11535621959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11535621941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5767810995 + 5767810996.

It is an arithmetic number, because the mean of its divisors is an integer number (5767810996).

Almost surely, 2^11535621991 is an apocalyptic number.

11535621991 is a deficient number, since it is larger than the sum of its proper divisors (1).

11535621991 is an equidigital number, since it uses as much as digits as its factorization.

11535621991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72900, while the sum is 43.

The spelling of 11535621991 in words is "eleven billion, five hundred thirty-five million, six hundred twenty-one thousand, nine hundred ninety-one".