6656781 has 8 divisors (see below), whose sum is σ = 9115744. Its totient is φ = 4317840.

The previous prime is 6656779. The next prime is 6656807. The reversal of 6656781 is 1876566.

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

It is not a de Polignac number, because 6656781 - 2¹ = 6656779 is a prime.

It is a super-2 number, since 2×6656781² = 88625466563922, which contains 22 as substring.

It is a Duffinian number.

6656781 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6656711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29875 + ... + 30096.

It is an arithmetic number, because the mean of its divisors is an integer number (1139468).

Almost surely, 2^6656781 is an apocalyptic number.

It is an amenable number.

6656781 is a deficient number, since it is larger than the sum of its proper divisors (2458963).

6656781 is a wasteful number, since it uses less digits than its factorization.

6656781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60011.

The product of its digits is 60480, while the sum is 39.

The square root of 6656781 is about 2580.0738361528. The cubic root of 6656781 is about 188.1141320712.

The spelling of 6656781 in words is "six million, six hundred fifty-six thousand, seven hundred eighty-one".