6439666915 has 16 divisors (see below), whose sum is σ = 8460563040. Its totient is φ = 4666475520.

The previous prime is 6439666889. The next prime is 6439666973. The reversal of 6439666915 is 5196669346.

It is not a de Polignac number, because 6439666915 - 2⁷ = 6439666787 is a prime.

It is a super-2 number, since 2×6439666915² = 82938619952291234450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 196110 + ... + 226579.

It is an arithmetic number, because the mean of its divisors is an integer number (528785190).

Almost surely, 2^6439666915 is an apocalyptic number.

6439666915 is a deficient number, since it is larger than the sum of its proper divisors (2020896125).

6439666915 is a wasteful number, since it uses less digits than its factorization.

6439666915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422982.

The product of its digits is 6298560, while the sum is 55.

The square root of 6439666915 is about 80247.5352581000. The cubic root of 6439666915 is about 1860.4634174051.

The spelling of 6439666915 in words is "six billion, four hundred thirty-nine million, six hundred sixty-six thousand, nine hundred fifteen".