997437643549 has 2 divisors, whose sum is σ = 997437643550. Its totient is φ = 997437643548.

The previous prime is 997437643511. The next prime is 997437643589. The reversal of 997437643549 is 945346734799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 997437643524 + 25 = 998718^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 997437643549 - 2¹⁵ = 997437610781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997437643589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498718821774 + 498718821775.

It is an arithmetic number, because the mean of its divisors is an integer number (498718821775).

Almost surely, 2^997437643549 is an apocalyptic number.

It is an amenable number.

997437643549 is a deficient number, since it is larger than the sum of its proper divisors (1).

997437643549 is an equidigital number, since it uses as much as digits as its factorization.

997437643549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 617258880, while the sum is 70.

The spelling of 997437643549 in words is "nine hundred ninety-seven billion, four hundred thirty-seven million, six hundred forty-three thousand, five hundred forty-nine".