6440081378 has 8 divisors (see below), whose sum is σ = 9661723740. Its totient is φ = 3219506800.

The previous prime is 6440081363. The next prime is 6440081441. The reversal of 6440081378 is 8731800446.

It can be written as a sum of positive squares in 2 ways, for example, as 6347786929 + 92294449 = 79673^2 + 9607^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 251693 + ... + 276096.

Almost surely, 2^6440081378 is an apocalyptic number.

6440081378 is a deficient number, since it is larger than the sum of its proper divisors (3221642362).

6440081378 is a wasteful number, since it uses less digits than its factorization.

6440081378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533892.

The product of its (nonzero) digits is 129024, while the sum is 41.

The square root of 6440081378 is about 80250.1176198515. The cubic root of 6440081378 is about 1860.5033302721.

The spelling of 6440081378 in words is "six billion, four hundred forty million, eighty-one thousand, three hundred seventy-eight".