491307997 has 2 divisors, whose sum is σ = 491307998. Its totient is φ = 491307996.

The previous prime is 491307989. The next prime is 491308019. The reversal of 491307997 is 799703194.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 302272996 + 189035001 = 17386^2 + 13749^2 .

It is a cyclic number.

It is not a de Polignac number, because 491307997 - 2³ = 491307989 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 491307997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491307097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245653998 + 245653999.

It is an arithmetic number, because the mean of its divisors is an integer number (245653999).

Almost surely, 2^491307997 is an apocalyptic number.

It is an amenable number.

491307997 is a deficient number, since it is larger than the sum of its proper divisors (1).

491307997 is an equidigital number, since it uses as much as digits as its factorization.

491307997 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 491307997 is about 22165.4685716319. The cubic root of 491307997 is about 789.0743829811.

The spelling of 491307997 in words is "four hundred ninety-one million, three hundred seven thousand, nine hundred ninety-seven".