8191957 has 4 divisors (see below), whose sum is σ = 8197696. Its totient is φ = 8186220.

The previous prime is 8191921. The next prime is 8191969. The reversal of 8191957 is 7591918.

It is a happy number.

8191957 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7591918 = 2 ⋅3795959.

It is a cyclic number.

It is not a de Polignac number, because 8191957 - 2⁷ = 8191829 is a prime.

It is a Duffinian number.

8191957 is a lucky number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8191357) 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, 1138 + ... + 4204.

It is an arithmetic number, because the mean of its divisors is an integer number (2049424).

Almost surely, 2^8191957 is an apocalyptic number.

It is an amenable number.

8191957 is a deficient number, since it is larger than the sum of its proper divisors (5739).

8191957 is a wasteful number, since it uses less digits than its factorization.

8191957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5738.

The product of its digits is 22680, while the sum is 40.

The square root of 8191957 is about 2862.1594993990. The cubic root of 8191957 is about 201.5870152703.

The spelling of 8191957 in words is "eight million, one hundred ninety-one thousand, nine hundred fifty-seven".