1968218991 has 12 divisors (see below), whose sum is σ = 2843841000. Its totient is φ = 1311750000.

The previous prime is 1968218983. The next prime is 1968219007. The reversal of 1968218991 is 1998128691.

It is not a de Polignac number, because 1968218991 - 2³ = 1968218983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1968218921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 241 + ... + 62741.

It is an arithmetic number, because the mean of its divisors is an integer number (236986750).

Almost surely, 2^1968218991 is an apocalyptic number.

1968218991 is a deficient number, since it is larger than the sum of its proper divisors (875622009).

1968218991 is a wasteful number, since it uses less digits than its factorization.

1968218991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66006 (or 66003 counting only the distinct ones).

The product of its digits is 559872, while the sum is 54.

The square root of 1968218991 is about 44364.6141761652. The cubic root of 1968218991 is about 1253.2117918597.

The spelling of 1968218991 in words is "one billion, nine hundred sixty-eight million, two hundred eighteen thousand, nine hundred ninety-one".