20158 has 4 divisors (see below), whose sum is σ = 30240. Its totient is φ = 10078.

The previous prime is 20149. The next prime is 20161. The reversal of 20158 is 85102.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

20158 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5038 + ... + 5041.

It is an arithmetic number, because the mean of its divisors is an integer number (7560).

2²⁰¹⁵⁸ is an apocalyptic number.

20158 is a deficient number, since it is larger than the sum of its proper divisors (10082).

20158 is a wasteful number, since it uses less digits than its factorization.

20158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10081.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 20158 is about 141.9788716676. The cubic root of 20158 is about 27.2154684219.

It can be divided in two parts, 20 and 158, that multiplied together give a triangular number (3160 = T₇₉).

The spelling of 20158 in words is "twenty thousand, one hundred fifty-eight".