1658 has 4 divisors (see below), whose sum is σ = 2490.
Its totient is φ = 828.
The previous prime is 1657. The next prime is 1663. The reversal of 1658 is 8561.
Subtracting 1658 from its reverse (8561), we obtain a triangular number (6903 = T117).
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8561 = 7 ⋅1223.
It can be written as a sum of positive squares in only one way, i.e., 1369 + 289 = 37^2 + 17^2
It is an alternating number because its digits alternate between odd and even.
It is a plaindrome in base 7, base 11 and base 16.
It is a nialpdrome in base 12 and base 14.
It is not an unprimeable number, because it can be changed into a prime (1657) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 413 + ... + 416.
21658 is an apocalyptic number.
1658 is a deficient number, since it is larger than the sum of its proper divisors (832).
1658 is an equidigital number, since it uses as much as digits as its factorization.
1658 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 831.
The product of its digits is 240, while the sum is 20.
The square root of 1658 is about 40.7185461430.
The cubic root of 1658 is about 11.8357243510.
The spelling of 1658 in words is "one thousand, six hundred fifty-eight".