161171977 has 4 divisors (see below), whose sum is σ = 164601216. Its totient is φ = 157742740.

The previous prime is 161171957. The next prime is 161171981. The reversal of 161171977 is 779171161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 779171161 = 23 ⋅33877007.

It is a cyclic number.

It is not a de Polignac number, because 161171977 - 2¹⁹ = 160647689 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161171947) 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, 1714549 + ... + 1714642.

It is an arithmetic number, because the mean of its divisors is an integer number (41150304).

Almost surely, 2^161171977 is an apocalyptic number.

It is an amenable number.

161171977 is a deficient number, since it is larger than the sum of its proper divisors (3429239).

161171977 is an equidigital number, since it uses as much as digits as its factorization.

161171977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3429238.

The product of its digits is 18522, while the sum is 40.

The square root of 161171977 is about 12695.3525748598. The cubic root of 161171977 is about 544.2058146134.

The spelling of 161171977 in words is "one hundred sixty-one million, one hundred seventy-one thousand, nine hundred seventy-seven".