161997 has 8 divisors (see below), whose sum is σ = 235680. Its totient is φ = 98160.

The previous prime is 161983. The next prime is 161999. The reversal of 161997 is 799161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161997 - 2⁷ = 161869 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 4909 = 161997 / (1 + 6 + 1 + 9 + 9 + 7).

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2422 + ... + 2487.

It is an arithmetic number, because the mean of its divisors is an integer number (29460).

2¹⁶¹⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

161997 is a deficient number, since it is larger than the sum of its proper divisors (73683).

161997 is a wasteful number, since it uses less digits than its factorization.

161997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4923.

The product of its digits is 3402, while the sum is 33.

The square root of 161997 is about 402.4885091527. The cubic root of 161997 is about 54.5132812791.

The spelling of 161997 in words is "one hundred sixty-one thousand, nine hundred ninety-seven".