161945161898 has 24 divisors (see below), whose sum is σ = 277897393452. Its totient is φ = 70347216384.

The previous prime is 161945161897. The next prime is 161945161901. The reversal of 161945161898 is 898161549161.

It can be written as a sum of positive squares in 6 ways, for example, as 105769999729 + 56175162169 = 325223^2 + 237013^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161945161891) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10768715 + ... + 10783742.

Almost surely, 2^161945161898 is an apocalyptic number.

161945161898 is a deficient number, since it is larger than the sum of its proper divisors (115952231554).

161945161898 is a wasteful number, since it uses less digits than its factorization.

161945161898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21552506 (or 21552489 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 59.

The spelling of 161945161898 in words is "one hundred sixty-one billion, nine hundred forty-five million, one hundred sixty-one thousand, eight hundred ninety-eight".