161887161719 has 4 divisors (see below), whose sum is σ = 165835629120. Its totient is φ = 157938694320.

The previous prime is 161887161707. The next prime is 161887161739. The reversal of 161887161719 is 917161788161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 917161788161 = 381209 ⋅2405929.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161887161719 is a prime.

It is a super-2 number, since 2×161887161719² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161887161739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1974233639 + ... + 1974233720.

It is an arithmetic number, because the mean of its divisors is an integer number (41458907280).

Almost surely, 2^161887161719 is an apocalyptic number.

161887161719 is a deficient number, since it is larger than the sum of its proper divisors (3948467401).

161887161719 is an equidigital number, since it uses as much as digits as its factorization.

161887161719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3948467400.

The product of its digits is 1016064, while the sum is 56.

The spelling of 161887161719 in words is "one hundred sixty-one billion, eight hundred eighty-seven million, one hundred sixty-one thousand, seven hundred nineteen".