16505210993 has 2 divisors, whose sum is σ = 16505210994. Its totient is φ = 16505210992.

The previous prime is 16505210989. The next prime is 16505211017. The reversal of 16505210993 is 39901250561.

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., 15696832369 + 808378624 = 125287^2 + 28432^2 .

It is a cyclic number.

It is not a de Polignac number, because 16505210993 - 2² = 16505210989 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16505210993.

It is not a weakly prime, because it can be changed into another prime (16505210963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8252605496 + 8252605497.

It is an arithmetic number, because the mean of its divisors is an integer number (8252605497).

Almost surely, 2^16505210993 is an apocalyptic number.

It is an amenable number.

16505210993 is a deficient number, since it is larger than the sum of its proper divisors (1).

16505210993 is an equidigital number, since it uses as much as digits as its factorization.

16505210993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72900, while the sum is 41.

The spelling of 16505210993 in words is "sixteen billion, five hundred five million, two hundred ten thousand, nine hundred ninety-three".