1997306491 has 2 divisors, whose sum is σ = 1997306492. Its totient is φ = 1997306490.

The previous prime is 1997306483. The next prime is 1997306551. The reversal of 1997306491 is 1946037991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1997306491 - 2³ = 1997306483 is a prime.

It is not a weakly prime, because it can be changed into another prime (1997306891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998653245 + 998653246.

It is an arithmetic number, because the mean of its divisors is an integer number (998653246).

Almost surely, 2^1997306491 is an apocalyptic number.

1997306491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997306491 is an equidigital number, since it uses as much as digits as its factorization.

1997306491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 1997306491 is about 44691.2350578947. The cubic root of 1997306491 is about 1259.3551943481.

The spelling of 1997306491 in words is "one billion, nine hundred ninety-seven million, three hundred six thousand, four hundred ninety-one".