6440779799 has 4 divisors (see below), whose sum is σ = 6444955536. Its totient is φ = 6436604064.

The previous prime is 6440779789. The next prime is 6440779837. The reversal of 6440779799 is 9979770446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9979770446 = 2 ⋅4989885223.

It is a cyclic number.

It is not a de Polignac number, because 6440779799 - 2¹⁶ = 6440714263 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 (6440779739) 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, 2085554 + ... + 2088639.

It is an arithmetic number, because the mean of its divisors is an integer number (1611238884).

Almost surely, 2^6440779799 is an apocalyptic number.

6440779799 is a deficient number, since it is larger than the sum of its proper divisors (4175737).

6440779799 is a wasteful number, since it uses less digits than its factorization.

6440779799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4175736.

The product of its (nonzero) digits is 24004512, while the sum is 62.

The square root of 6440779799 is about 80254.4690282105. The cubic root of 6440779799 is about 1860.5705844753.

The spelling of 6440779799 in words is "six billion, four hundred forty million, seven hundred seventy-nine thousand, seven hundred ninety-nine".