1216691668 has 12 divisors (see below), whose sum is σ = 2129862420. Its totient is φ = 608159552.

The previous prime is 1216691639. The next prime is 1216691701. The reversal of 1216691668 is 8661966121.

It can be written as a sum of positive squares in 2 ways, for example, as 1102372804 + 114318864 = 33202^2 + 10692^2 .

It is a super-2 number, since 2×1216691668² = 2960677229961244448, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31321 + ... + 58432.

It is an arithmetic number, because the mean of its divisors is an integer number (177488535).

Almost surely, 2^1216691668 is an apocalyptic number.

It is an amenable number.

1216691668 is a deficient number, since it is larger than the sum of its proper divisors (913170752).

1216691668 is a wasteful number, since it uses less digits than its factorization.

1216691668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93146 (or 93144 counting only the distinct ones).

The product of its digits is 186624, while the sum is 46.

The square root of 1216691668 is about 34881.1076085608. The cubic root of 1216691668 is about 1067.5629948181.

The spelling of 1216691668 in words is "one billion, two hundred sixteen million, six hundred ninety-one thousand, six hundred sixty-eight".