6439965457 has 4 divisors (see below), whose sum is σ = 6440454180. Its totient is φ = 6439476736.

The previous prime is 6439965443. The next prime is 6439965473. The reversal of 6439965457 is 7545699346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7545699346 = 2 ⋅3772849673.

It can be written as a sum of positive squares in 2 ways, for example, as 5428152976 + 1011812481 = 73676^2 + 31809^2 .

It is a cyclic number.

It is not a de Polignac number, because 6439965457 - 2²³ = 6431576849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6439905457) 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, 224032 + ... + 251137.

It is an arithmetic number, because the mean of its divisors is an integer number (1610113545).

Almost surely, 2^6439965457 is an apocalyptic number.

It is an amenable number.

6439965457 is a deficient number, since it is larger than the sum of its proper divisors (488723).

6439965457 is a wasteful number, since it uses less digits than its factorization.

6439965457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488722.

The product of its digits is 24494400, while the sum is 58.

The square root of 6439965457 is about 80249.3953684388. The cubic root of 6439965457 is about 1860.4921672299.

The spelling of 6439965457 in words is "six billion, four hundred thirty-nine million, nine hundred sixty-five thousand, four hundred fifty-seven".