1997111111 has 2 divisors, whose sum is σ = 1997111112. Its totient is φ = 1997111110.

The previous prime is 1997111093. The next prime is 1997111131. The reversal of 1997111111 is 1111117991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1997111111 - 2¹⁴ = 1997094727 is a prime.

1997111111 is a modest number, since divided by 111111 gives 1997 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1997111131) 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, 998555555 + 998555556.

It is an arithmetic number, because the mean of its divisors is an integer number (998555556).

Almost surely, 2^1997111111 is an apocalyptic number.

1997111111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997111111 is an equidigital number, since it uses as much as digits as its factorization.

1997111111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 567, while the sum is 32.

The square root of 1997111111 is about 44689.0491172054. The cubic root of 1997111111 is about 1259.3141289028.

The spelling of 1997111111 in words is "one billion, nine hundred ninety-seven million, one hundred eleven thousand, one hundred eleven".