191663 has 4 divisors (see below), whose sum is σ = 193200. Its totient is φ = 190128.

The previous prime is 191657. The next prime is 191669. The reversal of 191663 is 366191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 366191 = 7 ⋅52313.

It is an interprime number because it is at equal distance from previous prime (191657) and next prime (191669).

It is a cyclic number.

It is not a de Polignac number, because 191663 - 2⁶ = 191599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191669) 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, 563 + ... + 836.

It is an arithmetic number, because the mean of its divisors is an integer number (48300).

2¹⁹¹⁶⁶³ is an apocalyptic number.

191663 is a deficient number, since it is larger than the sum of its proper divisors (1537).

191663 is a wasteful number, since it uses less digits than its factorization.

191663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1536.

The product of its digits is 972, while the sum is 26.

The square root of 191663 is about 437.7933302370. The cubic root of 191663 is about 57.6562103992.

The spelling of 191663 in words is "one hundred ninety-one thousand, six hundred sixty-three".