491781011 has 4 divisors (see below), whose sum is σ = 501059952. Its totient is φ = 482502072.

The previous prime is 491781001. The next prime is 491781013. The reversal of 491781011 is 110187194.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491781011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (491781013) 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, 4639391 + ... + 4639496.

It is an arithmetic number, because the mean of its divisors is an integer number (125264988).

Almost surely, 2^491781011 is an apocalyptic number.

491781011 is a deficient number, since it is larger than the sum of its proper divisors (9278941).

491781011 is an equidigital number, since it uses as much as digits as its factorization.

491781011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9278940.

The product of its (nonzero) digits is 2016, while the sum is 32.

The square root of 491781011 is about 22176.1360701092. The cubic root of 491781011 is about 789.3275327464.

The spelling of 491781011 in words is "four hundred ninety-one million, seven hundred eighty-one thousand, eleven".