18365654521 has 2 divisors, whose sum is σ = 18365654522. Its totient is φ = 18365654520.

The previous prime is 18365654497. The next prime is 18365654627. The reversal of 18365654521 is 12545656381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13563164521 + 4802490000 = 116461^2 + 69300^2 .

It is a cyclic number.

It is not a de Polignac number, because 18365654521 - 2¹⁵ = 18365621753 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (18365654821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9182827260 + 9182827261.

It is an arithmetic number, because the mean of its divisors is an integer number (9182827261).

Almost surely, 2^18365654521 is an apocalyptic number.

It is an amenable number.

18365654521 is a deficient number, since it is larger than the sum of its proper divisors (1).

18365654521 is an equidigital number, since it uses as much as digits as its factorization.

18365654521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864000, while the sum is 46.

The spelling of 18365654521 in words is "eighteen billion, three hundred sixty-five million, six hundred fifty-four thousand, five hundred twenty-one".