491907973 has 2 divisors, whose sum is σ = 491907974. Its totient is φ = 491907972.

The previous prime is 491907961. The next prime is 491907979. The reversal of 491907973 is 379709194.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351675009 + 140232964 = 18753^2 + 11842^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491907973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491907979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245953986 + 245953987.

It is an arithmetic number, because the mean of its divisors is an integer number (245953987).

Almost surely, 2^491907973 is an apocalyptic number.

It is an amenable number.

491907973 is a deficient number, since it is larger than the sum of its proper divisors (1).

491907973 is an equidigital number, since it uses as much as digits as its factorization.

491907973 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 428652, while the sum is 49.

The square root of 491907973 is about 22178.9984670183. The cubic root of 491907973 is about 789.3954532078.

The spelling of 491907973 in words is "four hundred ninety-one million, nine hundred seven thousand, nine hundred seventy-three".