1678138978 has 8 divisors (see below), whose sum is σ = 2527741440. Its totient is φ = 835558500.

The previous prime is 1678138961. The next prime is 1678138991. The reversal of 1678138978 is 8798318761.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1754898 + ... + 1755853.

It is an arithmetic number, because the mean of its divisors is an integer number (315967680).

Almost surely, 2^1678138978 is an apocalyptic number.

1678138978 is a deficient number, since it is larger than the sum of its proper divisors (849602462).

1678138978 is a wasteful number, since it uses less digits than its factorization.

1678138978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3510992.

The product of its digits is 4064256, while the sum is 58.

The square root of 1678138978 is about 40965.0946294525. The cubic root of 1678138978 is about 1188.3452692590.

The spelling of 1678138978 in words is "one billion, six hundred seventy-eight million, one hundred thirty-eight thousand, nine hundred seventy-eight".