161178523901 has 2 divisors, whose sum is σ = 161178523902. Its totient is φ = 161178523900.

The previous prime is 161178523873. The next prime is 161178523943. The reversal of 161178523901 is 109325871161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158005455001 + 3173068900 = 397499^2 + 56330^2 .

It is a cyclic number.

It is not a de Polignac number, because 161178523901 - 2⁶ = 161178523837 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161178523991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80589261950 + 80589261951.

It is an arithmetic number, because the mean of its divisors is an integer number (80589261951).

Almost surely, 2^161178523901 is an apocalyptic number.

It is an amenable number.

161178523901 is a deficient number, since it is larger than the sum of its proper divisors (1).

161178523901 is an equidigital number, since it uses as much as digits as its factorization.

161178523901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 44.

The spelling of 161178523901 in words is "one hundred sixty-one billion, one hundred seventy-eight million, five hundred twenty-three thousand, nine hundred one".