1668512978 has 16 divisors (see below), whose sum is σ = 2763192096. Its totient is φ = 749276640.

The previous prime is 1668512971. The next prime is 1668513001. The reversal of 1668512978 is 8792158661.

It is not an unprimeable number, because it can be changed into a prime (1668512971) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 455051 + ... + 458702.

It is an arithmetic number, because the mean of its divisors is an integer number (172699506).

Almost surely, 2^1668512978 is an apocalyptic number.

1668512978 is a deficient number, since it is larger than the sum of its proper divisors (1094679118).

1668512978 is a wasteful number, since it uses less digits than its factorization.

1668512978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913849.

The product of its digits is 1451520, while the sum is 53.

The square root of 1668512978 is about 40847.4353907317. The cubic root of 1668512978 is about 1186.0687487578.

The spelling of 1668512978 in words is "one billion, six hundred sixty-eight million, five hundred twelve thousand, nine hundred seventy-eight".