18069517561 has 2 divisors, whose sum is σ = 18069517562. Its totient is φ = 18069517560.

The previous prime is 18069517559. The next prime is 18069517589. The reversal of 18069517561 is 16571596081.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14768325625 + 3301191936 = 121525^2 + 57456^2 .

It is a cyclic number.

It is not a de Polignac number, because 18069517561 - 2¹ = 18069517559 is a prime.

Together with 18069517559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18069512561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9034758780 + 9034758781.

It is an arithmetic number, because the mean of its divisors is an integer number (9034758781).

Almost surely, 2^18069517561 is an apocalyptic number.

It is an amenable number.

18069517561 is a deficient number, since it is larger than the sum of its proper divisors (1).

18069517561 is an equidigital number, since it uses as much as digits as its factorization.

18069517561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 453600, while the sum is 49.

The spelling of 18069517561 in words is "eighteen billion, sixty-nine million, five hundred seventeen thousand, five hundred sixty-one".