13611013121581 has 2 divisors, whose sum is σ = 13611013121582. Its totient is φ = 13611013121580.

The previous prime is 13611013121569. The next prime is 13611013121593. The reversal of 13611013121581 is 18512131011631.

It is a balanced prime because it is at equal distance from previous prime (13611013121569) and next prime (13611013121593).

It can be written as a sum of positive squares in only one way, i.e., 7771081727556 + 5839931394025 = 2787666^2 + 2416595^2 .

It is a cyclic number.

It is not a de Polignac number, because 13611013121581 - 2¹⁹ = 13611012597293 is a prime.

It is a super-2 number, since 2×13611013121581² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13611013121081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6805506560790 + 6805506560791.

It is an arithmetic number, because the mean of its divisors is an integer number (6805506560791).

Almost surely, 2^{13611013121581} is an apocalyptic number.

It is an amenable number.

13611013121581 is a deficient number, since it is larger than the sum of its proper divisors (1).

13611013121581 is an equidigital number, since it uses as much as digits as its factorization.

13611013121581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 34.

The spelling of 13611013121581 in words is "thirteen trillion, six hundred eleven billion, thirteen million, one hundred twenty-one thousand, five hundred eighty-one".