6443878257 has 6 divisors (see below), whose sum is σ = 9307824162. Its totient is φ = 4295918832.

The previous prime is 6443878211. The next prime is 6443878261. The reversal of 6443878257 is 7528783446.

6443878257 is a `hidden beast` number, since 6 + 4 + 4 + 387 + 8 + 257 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6441025536 + 2852721 = 80256^2 + 1689^2 .

It is not a de Polignac number, because 6443878257 - 2⁶ = 6443878193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6443878297) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 357993228 + ... + 357993245.

It is an arithmetic number, because the mean of its divisors is an integer number (1551304027).

Almost surely, 2^6443878257 is an apocalyptic number.

It is an amenable number.

6443878257 is a deficient number, since it is larger than the sum of its proper divisors (2863945905).

6443878257 is a wasteful number, since it uses less digits than its factorization.

6443878257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715986479 (or 715986476 counting only the distinct ones).

The product of its digits is 9031680, while the sum is 54.

The square root of 6443878257 is about 80273.7706663889. The cubic root of 6443878257 is about 1860.8688907778.

The spelling of 6443878257 in words is "six billion, four hundred forty-three million, eight hundred seventy-eight thousand, two hundred fifty-seven".