191023867439 has 4 divisors (see below), whose sum is σ = 192714344256. Its totient is φ = 189333390624.

The previous prime is 191023867387. The next prime is 191023867453. The reversal of 191023867439 is 934768320191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 934768320191 = 67 ⋅13951765973.

It is a cyclic number.

It is not a de Polignac number, because 191023867439 - 2¹² = 191023863343 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 (191023867469) 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, 845238239 + ... + 845238464.

It is an arithmetic number, because the mean of its divisors is an integer number (48178586064).

Almost surely, 2^191023867439 is an apocalyptic number.

191023867439 is a deficient number, since it is larger than the sum of its proper divisors (1690476817).

191023867439 is a wasteful number, since it uses less digits than its factorization.

191023867439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1690476816.

The product of its (nonzero) digits is 1959552, while the sum is 53.

The spelling of 191023867439 in words is "one hundred ninety-one billion, twenty-three million, eight hundred sixty-seven thousand, four hundred thirty-nine".