158421 has 4 divisors (see below), whose sum is σ = 211232. Its totient is φ = 105612.
The previous prime is 158419. The next prime is 158429. The reversal of 158421 is 124851.
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: 124851 = 3 ⋅41617.
It is not a de Polignac number, because 158421 - 21 = 158419 is a prime.
It is a D-number.
It is a Duffinian number.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 158421.
It is not an unprimeable number, because it can be changed into a prime (158429) 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, 26401 + ... + 26406.
It is an arithmetic number, because the mean of its divisors is an integer number (52808).
2158421 is an apocalyptic number.
It is an amenable number.
158421 is a deficient number, since it is larger than the sum of its proper divisors (52811).
158421 is an equidigital number, since it uses as much as digits as its factorization.
158421 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 52810.
The product of its digits is 320, while the sum is 21.
The square root of 158421 is about 398.0213562109. The cubic root of 158421 is about 54.1091755569.
The spelling of 158421 in words is "one hundred fifty-eight thousand, four hundred twenty-one".
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