1663720271 has 2 divisors, whose sum is σ = 1663720272. Its totient is φ = 1663720270.

The previous prime is 1663720259. The next prime is 1663720277. The reversal of 1663720271 is 1720273661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1663720271 - 2¹⁰ = 1663719247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1663720277) 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 as a sum of consecutive naturals, namely, 831860135 + 831860136.

It is an arithmetic number, because the mean of its divisors is an integer number (831860136).

Almost surely, 2^1663720271 is an apocalyptic number.

1663720271 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663720271 is an equidigital number, since it uses as much as digits as its factorization.

1663720271 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21168, while the sum is 35.

The square root of 1663720271 is about 40788.7272539853. The cubic root of 1663720271 is about 1184.9320217136.

The spelling of 1663720271 in words is "one billion, six hundred sixty-three million, seven hundred twenty thousand, two hundred seventy-one".