18033399661 has 2 divisors, whose sum is σ = 18033399662. Its totient is φ = 18033399660.

The previous prime is 18033399647. The next prime is 18033399667. The reversal of 18033399661 is 16699333081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10099044036 + 7934355625 = 100494^2 + 89075^2 .

It is a cyclic number.

It is not a de Polignac number, because 18033399661 - 2¹³ = 18033391469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18033399667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9016699830 + 9016699831.

It is an arithmetic number, because the mean of its divisors is an integer number (9016699831).

Almost surely, 2^18033399661 is an apocalyptic number.

It is an amenable number.

18033399661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18033399661 is an equidigital number, since it uses as much as digits as its factorization.

18033399661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 629856, while the sum is 49.

The spelling of 18033399661 in words is "eighteen billion, thirty-three million, three hundred ninety-nine thousand, six hundred sixty-one".