161558 has 4 divisors (see below), whose sum is σ = 242340. Its totient is φ = 80778.

The previous prime is 161543. The next prime is 161561. The reversal of 161558 is 855161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 855161 = 463 ⋅1847.

It is a super-2 number, since 2×161558² = 52201974728, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40388 + ... + 40391.

It is an arithmetic number, because the mean of its divisors is an integer number (60585).

2¹⁶¹⁵⁵⁸ is an apocalyptic number.

161558 is a deficient number, since it is larger than the sum of its proper divisors (80782).

161558 is an equidigital number, since it uses as much as digits as its factorization.

161558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80781.

The product of its digits is 1200, while the sum is 26.

The square root of 161558 is about 401.9427819976. The cubic root of 161558 is about 54.4639943983.

The spelling of 161558 in words is "one hundred sixty-one thousand, five hundred fifty-eight".