6401778 has 16 divisors (see below), whose sum is σ = 12882240. Its totient is φ = 2120816.

The previous prime is 6401771. The next prime is 6401827. The reversal of 6401778 is 8771046.

It is a super-2 number, since 2×6401778² = 81965523122568, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (6401771) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2193 + ... + 4196.

It is an arithmetic number, because the mean of its divisors is an integer number (805140).

Almost surely, 2^6401778 is an apocalyptic number.

6401778 is an abundant number, since it is smaller than the sum of its proper divisors (6480462).

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

6401778 is a wasteful number, since it uses less digits than its factorization.

6401778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6561.

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 6401778 is about 2530.1735118367. The cubic root of 6401778 is about 185.6807449712.

The spelling of 6401778 in words is "six million, four hundred one thousand, seven hundred seventy-eight".