191651 has 4 divisors (see below), whose sum is σ = 196152. Its totient is φ = 187152.

The previous prime is 191627. The next prime is 191657. The reversal of 191651 is 156191.

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

It is a cyclic number.

It is not a de Polignac number, because 191651 - 2¹⁴ = 175267 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 191651.

It is not an unprimeable number, because it can be changed into a prime (191657) 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, 2186 + ... + 2271.

It is an arithmetic number, because the mean of its divisors is an integer number (49038).

2¹⁹¹⁶⁵¹ is an apocalyptic number.

191651 is a deficient number, since it is larger than the sum of its proper divisors (4501).

191651 is an equidigital number, since it uses as much as digits as its factorization.

191651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4500.

The product of its digits is 270, while the sum is 23.

The square root of 191651 is about 437.7796249256. The cubic root of 191651 is about 57.6550070910.

The spelling of 191651 in words is "one hundred ninety-one thousand, six hundred fifty-one".