6640378 has 4 divisors (see below), whose sum is σ = 9960570. Its totient is φ = 3320188.

The previous prime is 6640373. The next prime is 6640393. The reversal of 6640378 is 8730466.

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

It can be written as a sum of positive squares in only one way, i.e., 5414929 + 1225449 = 2327^2 + 1107^2 .

It is a super-3 number, since 3×6640378³ (a number of 21 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (6640373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1660093 + ... + 1660096.

Almost surely, 2^6640378 is an apocalyptic number.

6640378 is a deficient number, since it is larger than the sum of its proper divisors (3320192).

6640378 is a wasteful number, since it uses less digits than its factorization.

6640378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3320191.

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 6640378 is about 2576.8930905259. The cubic root of 6640378 is about 187.9594940649.

It can be divided in two parts, 6640 and 378, that multiplied together give a triangular number (2509920 = T₂₂₄₀).

The spelling of 6640378 in words is "six million, six hundred forty thousand, three hundred seventy-eight".