1663566978 has 16 divisors (see below), whose sum is σ = 3327736896. Its totient is φ = 554421840.

The previous prime is 1663566941. The next prime is 1663567019. The reversal of 1663566978 is 8796653661.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15900 + ... + 59832.

It is an arithmetic number, because the mean of its divisors is an integer number (207983556).

Almost surely, 2^1663566978 is an apocalyptic number.

1663566978 is an abundant number, since it is smaller than the sum of its proper divisors (1664169918).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1663566978 is a wasteful number, since it uses less digits than its factorization.

1663566978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50249.

The product of its digits is 9797760, while the sum is 57.

The square root of 1663566978 is about 40786.8481008278. The cubic root of 1663566978 is about 1184.8956279026.

The spelling of 1663566978 in words is "one billion, six hundred sixty-three million, five hundred sixty-six thousand, nine hundred seventy-eight".