6440778994 has 16 divisors (see below), whose sum is σ = 10646298432. Its totient is φ = 2903534928.

The previous prime is 6440778947. The next prime is 6440779019. The reversal of 6440778994 is 4998770446.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2879374 + ... + 2881609.

It is an arithmetic number, because the mean of its divisors is an integer number (665393652).

Almost surely, 2^6440778994 is an apocalyptic number.

6440778994 is a deficient number, since it is larger than the sum of its proper divisors (4205519438).

6440778994 is a wasteful number, since it uses less digits than its factorization.

6440778994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5761041.

The product of its (nonzero) digits is 12192768, while the sum is 58.

The square root of 6440778994 is about 80254.4640129133. The cubic root of 6440778994 is about 1860.5705069609.

The spelling of 6440778994 in words is "six billion, four hundred forty million, seven hundred seventy-eight thousand, nine hundred ninety-four".