6646381 has 16 divisors (see below), whose sum is σ = 7907328. Its totient is φ = 5468400.

The previous prime is 6646373. The next prime is 6646399. The reversal of 6646381 is 1836466.

It is not a de Polignac number, because 6646381 - 2³ = 6646373 is a prime.

It is a super-2 number, since 2×6646381² = 88348760794322, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

Its product of digits (20736) is a multiple of the sum of its prime divisors (432).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6646331) 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 in 15 ways as a sum of consecutive naturals, for example, 21216 + ... + 21526.

It is an arithmetic number, because the mean of its divisors is an integer number (494208).

Almost surely, 2^6646381 is an apocalyptic number.

It is an amenable number.

6646381 is a deficient number, since it is larger than the sum of its proper divisors (1260947).

6646381 is a wasteful number, since it uses less digits than its factorization.

6646381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432.

The product of its digits is 20736, while the sum is 34.

The square root of 6646381 is about 2578.0576021493. The cubic root of 6646381 is about 188.0161163941.

The spelling of 6646381 in words is "six million, six hundred forty-six thousand, three hundred eighty-one".