1663216993 has 2 divisors, whose sum is σ = 1663216994. Its totient is φ = 1663216992.

The previous prime is 1663216979. The next prime is 1663217051. The reversal of 1663216993 is 3996123661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1444532049 + 218684944 = 38007^2 + 14788^2 .

It is a cyclic number.

It is not a de Polignac number, because 1663216993 - 2⁹ = 1663216481 is a prime.

It is not a weakly prime, because it can be changed into another prime (1663216943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831608496 + 831608497.

It is an arithmetic number, because the mean of its divisors is an integer number (831608497).

Almost surely, 2^1663216993 is an apocalyptic number.

It is an amenable number.

1663216993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663216993 is an equidigital number, since it uses as much as digits as its factorization.

1663216993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 46.

The square root of 1663216993 is about 40782.5574602673. The cubic root of 1663216993 is about 1184.8125283968.

The spelling of 1663216993 in words is "one billion, six hundred sixty-three million, two hundred sixteen thousand, nine hundred ninety-three".