165861958 has 4 divisors (see below), whose sum is σ = 248792940. Its totient is φ = 82930978.

The previous prime is 165861929. The next prime is 165861959. The reversal of 165861958 is 859168561.

165861958 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 859168561 = 59 ⋅14562179.

It is a super-2 number, since 2×165861958² = 55020378223187528, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165861959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41465488 + ... + 41465491.

It is an arithmetic number, because the mean of its divisors is an integer number (62198235).

Almost surely, 2^165861958 is an apocalyptic number.

165861958 is a deficient number, since it is larger than the sum of its proper divisors (82930982).

165861958 is an equidigital number, since it uses as much as digits as its factorization.

165861958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82930981.

The product of its digits is 518400, while the sum is 49.

The square root of 165861958 is about 12878.7405440128. The cubic root of 165861958 is about 549.4340823666.

The spelling of 165861958 in words is "one hundred sixty-five million, eight hundred sixty-one thousand, nine hundred fifty-eight".