161293457081 has 2 divisors, whose sum is σ = 161293457082. Its totient is φ = 161293457080.

The previous prime is 161293457053. The next prime is 161293457093. The reversal of 161293457081 is 180754392161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142672398400 + 18621058681 = 377720^2 + 136459^2 .

It is a cyclic number.

It is not a de Polignac number, because 161293457081 - 2²² = 161289262777 is a prime.

It is a super-2 number, since 2×161293457081² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (161293457681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80646728540 + 80646728541.

It is an arithmetic number, because the mean of its divisors is an integer number (80646728541).

It is a 1-persistent number, because it is pandigital, but 2⋅161293457081 = 322586914162 is not.

Almost surely, 2^161293457081 is an apocalyptic number.

It is an amenable number.

161293457081 is a deficient number, since it is larger than the sum of its proper divisors (1).

161293457081 is an equidigital number, since it uses as much as digits as its factorization.

161293457081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 362880, while the sum is 47.

The spelling of 161293457081 in words is "one hundred sixty-one billion, two hundred ninety-three million, four hundred fifty-seven thousand, eighty-one".