6436721878 has 16 divisors (see below), whose sum is σ = 9775696896. Its totient is φ = 3178190440.

The previous prime is 6436721873. The next prime is 6436721969. The reversal of 6436721878 is 8781276346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6436721873) 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, 442875 + ... + 457177.

It is an arithmetic number, because the mean of its divisors is an integer number (610981056).

Almost surely, 2^6436721878 is an apocalyptic number.

6436721878 is a deficient number, since it is larger than the sum of its proper divisors (3338975018).

6436721878 is a wasteful number, since it uses less digits than its factorization.

6436721878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17099.

The product of its digits is 2709504, while the sum is 52.

The square root of 6436721878 is about 80229.1834558971. The cubic root of 6436721878 is about 1860.1797604427.

The spelling of 6436721878 in words is "six billion, four hundred thirty-six million, seven hundred twenty-one thousand, eight hundred seventy-eight".