161505397 has 2 divisors, whose sum is σ = 161505398. Its totient is φ = 161505396.

The previous prime is 161505359. The next prime is 161505401. The reversal of 161505397 is 793505161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 99820081 + 61685316 = 9991^2 + 7854^2 .

It is a cyclic number.

It is not a de Polignac number, because 161505397 - 2⁷ = 161505269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161505307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80752698 + 80752699.

It is an arithmetic number, because the mean of its divisors is an integer number (80752699).

Almost surely, 2^161505397 is an apocalyptic number.

It is an amenable number.

161505397 is a deficient number, since it is larger than the sum of its proper divisors (1).

161505397 is an equidigital number, since it uses as much as digits as its factorization.

161505397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28350, while the sum is 37.

The square root of 161505397 is about 12708.4773674898. The cubic root of 161505397 is about 544.5808262979.

The spelling of 161505397 in words is "one hundred sixty-one million, five hundred five thousand, three hundred ninety-seven".