491990093 has 4 divisors (see below), whose sum is σ = 562274400. Its totient is φ = 421705788.

The previous prime is 491990087. The next prime is 491990099. The reversal of 491990093 is 390099194.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 390099194 = 2 ⋅195049597.

It is an interprime number because it is at equal distance from previous prime (491990087) and next prime (491990099).

It is not a de Polignac number, because 491990093 - 2²⁶ = 424881229 is a prime.

It is a super-2 number, since 2×491990093² = 484108503220297298, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491990099) 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, 35142143 + ... + 35142156.

It is an arithmetic number, because the mean of its divisors is an integer number (140568600).

Almost surely, 2^491990093 is an apocalyptic number.

It is an amenable number.

491990093 is a deficient number, since it is larger than the sum of its proper divisors (70284307).

491990093 is an equidigital number, since it uses as much as digits as its factorization.

491990093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70284306.

The product of its (nonzero) digits is 78732, while the sum is 44.

The square root of 491990093 is about 22180.8496906678. The cubic root of 491990093 is about 789.4393784615.

The spelling of 491990093 in words is "four hundred ninety-one million, nine hundred ninety thousand, ninety-three".