161505113993 has 2 divisors, whose sum is σ = 161505113994. Its totient is φ = 161505113992.

The previous prime is 161505113909. The next prime is 161505113999. The reversal of 161505113993 is 399311505161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 92846965264 + 68658148729 = 304708^2 + 262027^2 .

It is an emirp because it is prime and its reverse (399311505161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161505113993 - 2¹² = 161505109897 is a prime.

It is not a weakly prime, because it can be changed into another prime (161505113999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80752556996 + 80752556997.

It is an arithmetic number, because the mean of its divisors is an integer number (80752556997).

Almost surely, 2^161505113993 is an apocalyptic number.

It is an amenable number.

161505113993 is a deficient number, since it is larger than the sum of its proper divisors (1).

161505113993 is an equidigital number, since it uses as much as digits as its factorization.

161505113993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 109350, while the sum is 44.

The spelling of 161505113993 in words is "one hundred sixty-one billion, five hundred five million, one hundred thirteen thousand, nine hundred ninety-three".