991626983423 has 4 divisors (see below), whose sum is σ = 1001254429968. Its totient is φ = 981999536880.

The previous prime is 991626983393. The next prime is 991626983447. The reversal of 991626983423 is 324389626199.

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 991626983423 - 2¹⁶ = 991626917887 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 (991626983023) 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, 4813723118 + ... + 4813723323.

It is an arithmetic number, because the mean of its divisors is an integer number (250313607492).

Almost surely, 2^991626983423 is an apocalyptic number.

991626983423 is a deficient number, since it is larger than the sum of its proper divisors (9627446545).

991626983423 is a wasteful number, since it uses less digits than its factorization.

991626983423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9627446544.

The product of its digits is 30233088, while the sum is 62.

The spelling of 991626983423 in words is "nine hundred ninety-one billion, six hundred twenty-six million, nine hundred eighty-three thousand, four hundred twenty-three".