6440646 has 8 divisors (see below), whose sum is σ = 12881304. Its totient is φ = 2146880.

The previous prime is 6440641. The next prime is 6440647. The reversal of 6440646 is 6460446.

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

6440646 is an admirable number.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440641) 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, 536715 + ... + 536726.

It is an arithmetic number, because the mean of its divisors is an integer number (1610163).

Almost surely, 2^6440646 is an apocalyptic number.

6440646 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6440646 is a wasteful number, since it uses less digits than its factorization.

6440646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1073446.

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 6440646 is about 2537.8427847288. The cubic root of 6440646 is about 186.0557700724.

It can be divided in two parts, 6 and 440646, that multiplied together give a square (2643876 = 1626²).

The spelling of 6440646 in words is "six million, four hundred forty thousand, six hundred forty-six".