491372991 has 6 divisors (see below), whose sum is σ = 709761000. Its totient is φ = 327581988.

The previous prime is 491372983. The next prime is 491373011. The reversal of 491372991 is 199273194.

491372991 is a `hidden beast` number, since 491 + 3 + 72 + 9 + 91 = 666.

It is not a de Polignac number, because 491372991 - 2³ = 491372983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (491372941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 27298491 + ... + 27298508.

It is an arithmetic number, because the mean of its divisors is an integer number (118293500).

Almost surely, 2^491372991 is an apocalyptic number.

491372991 is a deficient number, since it is larger than the sum of its proper divisors (218388009).

491372991 is a wasteful number, since it uses less digits than its factorization.

491372991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54597005 (or 54597002 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 491372991 is about 22166.9346324655. The cubic root of 491372991 is about 789.1091763894.

The spelling of 491372991 in words is "four hundred ninety-one million, three hundred seventy-two thousand, nine hundred ninety-one".