991834296478 has 4 divisors (see below), whose sum is σ = 1487751444720. Its totient is φ = 495917148238.

The previous prime is 991834296407. The next prime is 991834296493. The reversal of 991834296478 is 874692438199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 874692438199 = 5021 ⋅174206819.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 247958574118 + ... + 247958574121.

It is an arithmetic number, because the mean of its divisors is an integer number (371937861180).

Almost surely, 2^991834296478 is an apocalyptic number.

991834296478 is a deficient number, since it is larger than the sum of its proper divisors (495917148242).

991834296478 is a wasteful number, since it uses less digits than its factorization.

991834296478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495917148241.

The product of its digits is 188116992, while the sum is 70.

The spelling of 991834296478 in words is "nine hundred ninety-one billion, eight hundred thirty-four million, two hundred ninety-six thousand, four hundred seventy-eight".