1663686979 has 2 divisors, whose sum is σ = 1663686980. Its totient is φ = 1663686978.

The previous prime is 1663686961. The next prime is 1663687027. The reversal of 1663686979 is 9796863661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1663686979 - 2⁹ = 1663686467 is a prime.

It is not a weakly prime, because it can be changed into another prime (1663686679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831843489 + 831843490.

It is an arithmetic number, because the mean of its divisors is an integer number (831843490).

Almost surely, 2^1663686979 is an apocalyptic number.

1663686979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663686979 is an equidigital number, since it uses as much as digits as its factorization.

1663686979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17635968, while the sum is 61.

The square root of 1663686979 is about 40788.3191489917. The cubic root of 1663686979 is about 1184.9241179370.

The spelling of 1663686979 in words is "one billion, six hundred sixty-three million, six hundred eighty-six thousand, nine hundred seventy-nine".