680844649 has 9 divisors (see below), whose sum is σ = 690502917. Its totient is φ = 671320704.

The previous prime is 680844617. The next prime is 680844707. The reversal of 680844649 is 946448086.

It is a happy number.

The square root of 680844649 is 26093.

It is a perfect power (a square), and thus also a powerful number.

680844649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 202635225 + 478209424 = 14235^2 + 21868^2 .

It is not a de Polignac number, because 680844649 - 2⁵ = 680844617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (680844349) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2530887 + ... + 2531155.

Almost surely, 2^680844649 is an apocalyptic number.

680844649 is the 26093-rd square number.

680844649 is the 13047-th centered octagonal number.

It is an amenable number.

680844649 is a deficient number, since it is larger than the sum of its proper divisors (9658268).

680844649 is an frugal number, since it uses more digits than its factorization.

680844649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 732 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 49.

The cubic root of 680844649 is about 879.7298796454.

Multiplying 680844649 by its sum of digits (49), we get a square (33361387801 = 182651²).

Multiplying 680844649 by its product of nonzero digits (1327104), we get a square (903551657066496 = 30059136²).

The spelling of 680844649 in words is "six hundred eighty million, eight hundred forty-four thousand, six hundred forty-nine".