291191023 has 4 divisors (see below), whose sum is σ = 292324320. Its totient is φ = 290057728.

The previous prime is 291191009. The next prime is 291191057. The reversal of 291191023 is 320191192.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-291191023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 291190982 and 291191000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291192023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 566263 + ... + 566776.

It is an arithmetic number, because the mean of its divisors is an integer number (73081080).

Almost surely, 2^291191023 is an apocalyptic number.

291191023 is a deficient number, since it is larger than the sum of its proper divisors (1133297).

291191023 is a wasteful number, since it uses less digits than its factorization.

291191023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1133296.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 291191023 is about 17064.3201739770. The cubic root of 291191023 is about 662.8155073914.

The spelling of 291191023 in words is "two hundred ninety-one million, one hundred ninety-one thousand, twenty-three".