18821333497 has 2 divisors, whose sum is σ = 18821333498. Its totient is φ = 18821333496.

The previous prime is 18821333429. The next prime is 18821333507. The reversal of 18821333497 is 79433312881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11446646121 + 7374687376 = 106989^2 + 85876^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18821333497 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18821333497.

It is not a weakly prime, because it can be changed into another prime (18821333417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9410666748 + 9410666749.

It is an arithmetic number, because the mean of its divisors is an integer number (9410666749).

Almost surely, 2^18821333497 is an apocalyptic number.

It is an amenable number.

18821333497 is a deficient number, since it is larger than the sum of its proper divisors (1).

18821333497 is an equidigital number, since it uses as much as digits as its factorization.

18821333497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 49.

The spelling of 18821333497 in words is "eighteen billion, eight hundred twenty-one million, three hundred thirty-three thousand, four hundred ninety-seven".