991663093 has 8 divisors (see below), whose sum is σ = 1000553400. Its totient is φ = 982802880.

The previous prime is 991663073. The next prime is 991663097. The reversal of 991663093 is 390366199.

It can be written as a sum of positive squares in 4 ways, for example, as 6770404 + 984892689 = 2602^2 + 31383^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991663093 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 (991663097) 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, 61471 + ... + 75907.

It is an arithmetic number, because the mean of its divisors is an integer number (125069175).

Almost surely, 2^991663093 is an apocalyptic number.

It is an amenable number.

991663093 is a deficient number, since it is larger than the sum of its proper divisors (8890307).

991663093 is a wasteful number, since it uses less digits than its factorization.

991663093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15047.

The product of its (nonzero) digits is 236196, while the sum is 46.

The square root of 991663093 is about 31490.6826378851. The cubic root of 991663093 is about 997.2132723628.

The spelling of 991663093 in words is "nine hundred ninety-one million, six hundred sixty-three thousand, ninety-three".