1663508779 has 4 divisors (see below), whose sum is σ = 1671953184. Its totient is φ = 1655064376.

The previous prime is 1663508753. The next prime is 1663508783. The reversal of 1663508779 is 9778053661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9778053661 = 131 ⋅74641631.

It is a cyclic number.

It is not a de Polignac number, because 1663508779 - 2⁵ = 1663508747 is a prime.

It is a super-2 number, since 2×1663508779² = 5534522915620141682, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1664508779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4221907 + ... + 4222300.

It is an arithmetic number, because the mean of its divisors is an integer number (417988296).

Almost surely, 2^1663508779 is an apocalyptic number.

1663508779 is a deficient number, since it is larger than the sum of its proper divisors (8444405).

1663508779 is an equidigital number, since it uses as much as digits as its factorization.

1663508779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8444404.

The product of its (nonzero) digits is 1905120, while the sum is 52.

The square root of 1663508779 is about 40786.1346415666. The cubic root of 1663508779 is about 1184.8818100951.

The spelling of 1663508779 in words is "one billion, six hundred sixty-three million, five hundred eight thousand, seven hundred seventy-nine".