991163623 has 8 divisors (see below), whose sum is σ = 996363648. Its totient is φ = 985976544.

The previous prime is 991163617. The next prime is 991163639. The reversal of 991163623 is 326361199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 991163623 - 2⁹ = 991163111 is a prime.

It is a super-2 number, since 2×991163623² = 1964810655116972258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991163323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 175065 + ... + 180637.

It is an arithmetic number, because the mean of its divisors is an integer number (124545456).

Almost surely, 2^991163623 is an apocalyptic number.

991163623 is a deficient number, since it is larger than the sum of its proper divisors (5200025).

991163623 is a wasteful number, since it uses less digits than its factorization.

With its successor (991163624) it forms an eRAP, since the sums of their prime factors are consecutive (6473 and 6474).

991163623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6473.

The product of its digits is 52488, while the sum is 40.

The square root of 991163623 is about 31482.7511980767. The cubic root of 991163623 is about 997.0458224287.

The spelling of 991163623 in words is "nine hundred ninety-one million, one hundred sixty-three thousand, six hundred twenty-three".