161162172865 has 4 divisors (see below), whose sum is σ = 193394607444. Its totient is φ = 128929738288.

The previous prime is 161162172841. The next prime is 161162172877. The reversal of 161162172865 is 568271261161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 568271261161 = 157 ⋅3619562173.

It can be written as a sum of positive squares in 2 ways, for example, as 44401232656 + 116760940209 = 210716^2 + 341703^2 .

It is a cyclic number.

It is not a de Polignac number, because 161162172865 - 2¹³ = 161162164673 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16116217282 + ... + 16116217291.

It is an arithmetic number, because the mean of its divisors is an integer number (48348651861).

Almost surely, 2^161162172865 is an apocalyptic number.

It is an amenable number.

161162172865 is a deficient number, since it is larger than the sum of its proper divisors (32232434579).

161162172865 is an equidigital number, since it uses as much as digits as its factorization.

161162172865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32232434578.

The product of its digits is 241920, while the sum is 46.

The spelling of 161162172865 in words is "one hundred sixty-one billion, one hundred sixty-two million, one hundred seventy-two thousand, eight hundred sixty-five".