1997598331 has 2 divisors, whose sum is σ = 1997598332. Its totient is φ = 1997598330.

The previous prime is 1997598313. The next prime is 1997598347. The reversal of 1997598331 is 1338957991.

Together with previous prime (1997598313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1997598331 - 2¹¹ = 1997596283 is a prime.

It is a super-2 number, since 2×1997598331² = 7980798184027971122, which contains 22 as substring.

It is the 44695-th Hogben number.

It is not a weakly prime, because it can be changed into another prime (1997598131) by changing a digit.

It is a nontrivial repunit in base 44694.

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, 998799165 + 998799166.

It is an arithmetic number, because the mean of its divisors is an integer number (998799166).

Almost surely, 2^1997598331 is an apocalyptic number.

1997598331 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997598331 is an equidigital number, since it uses as much as digits as its factorization.

1997598331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1837080, while the sum is 55.

The square root of 1997598331 is about 44694.5000083903. The cubic root of 1997598331 is about 1259.4165290043.

The spelling of 1997598331 in words is "one billion, nine hundred ninety-seven million, five hundred ninety-eight thousand, three hundred thirty-one".