6840866644 has 6 divisors (see below), whose sum is σ = 11971516634. Its totient is φ = 3420433320.

The previous prime is 6840866633. The next prime is 6840866651. The reversal of 6840866644 is 4466680486.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 6832675600 + 8191044 = 82660^2 + 2862^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6840866591 and 6840866600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 855108327 + ... + 855108334.

Almost surely, 2^6840866644 is an apocalyptic number.

It is an amenable number.

6840866644 is a deficient number, since it is larger than the sum of its proper divisors (5130649990).

6840866644 is a wasteful number, since it uses less digits than its factorization.

6840866644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1710216665 (or 1710216663 counting only the distinct ones).

The product of its (nonzero) digits is 5308416, while the sum is 52.

The square root of 6840866644 is about 82709.5317602512. The cubic root of 6840866644 is about 1898.3241588715.

The spelling of 6840866644 in words is "six billion, eight hundred forty million, eight hundred sixty-six thousand, six hundred forty-four".