1978668791 has 8 divisors (see below), whose sum is σ = 2158986000. Its totient is φ = 1798424640.

The previous prime is 1978668767. The next prime is 1978668793.

1978668791 is nontrivially palindromic in base 10.

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

It is a cyclic number.

It is not a de Polignac number, because 1978668791 - 2²⁶ = 1911559927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978668793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49235 + ... + 79883.

It is an arithmetic number, because the mean of its divisors is an integer number (269873250).

Almost surely, 2^1978668791 is an apocalyptic number.

1978668791 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1978668791 is a deficient number, since it is larger than the sum of its proper divisors (180317209).

1978668791 is a wasteful number, since it uses less digits than its factorization.

1978668791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36529.

The product of its digits is 9144576, while the sum is 62.

The square root of 1978668791 is about 44482.2300587549. The cubic root of 1978668791 is about 1255.4257569341.

The spelling of 1978668791 in words is "one billion, nine hundred seventy-eight million, six hundred sixty-eight thousand, seven hundred ninety-one".