491323021 has 4 divisors (see below), whose sum is σ = 561512032. Its totient is φ = 421134012.

The previous prime is 491323013. The next prime is 491323057. The reversal of 491323021 is 120323194.

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.

It is a cyclic number.

It is not a de Polignac number, because 491323021 - 2³ = 491323013 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 (491329021) 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 3 ways as a sum of consecutive naturals, for example, 35094495 + ... + 35094508.

It is an arithmetic number, because the mean of its divisors is an integer number (140378008).

Almost surely, 2^491323021 is an apocalyptic number.

It is an amenable number.

491323021 is a deficient number, since it is larger than the sum of its proper divisors (70189011).

491323021 is an equidigital number, since it uses as much as digits as its factorization.

491323021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70189010.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 491323021 is about 22165.8074745767. The cubic root of 491323021 is about 789.0824260911.

The spelling of 491323021 in words is "four hundred ninety-one million, three hundred twenty-three thousand, twenty-one".