6400009909 has 4 divisors (see below), whose sum is σ = 6402515404. Its totient is φ = 6397504416.

The previous prime is 6400009901. The next prime is 6400009919. The reversal of 6400009909 is 9099000046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3930913809 + 2469096100 = 62697^2 + 49690^2 .

It is a cyclic number.

It is not a de Polignac number, because 6400009909 - 2³ = 6400009901 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 (6400009901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1248912 + ... + 1254025.

It is an arithmetic number, because the mean of its divisors is an integer number (1600628851).

Almost surely, 2^6400009909 is an apocalyptic number.

It is an amenable number.

6400009909 is a deficient number, since it is larger than the sum of its proper divisors (2505495).

6400009909 is a wasteful number, since it uses less digits than its factorization.

6400009909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2505494.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 6400009909 is about 80000.0619312260. The cubic root of 6400009909 is about 1856.6364916426.

The spelling of 6400009909 in words is "six billion, four hundred million, nine thousand, nine hundred nine".