681996628 has 12 divisors (see below), whose sum is σ = 1194106900. Its totient is φ = 340823232.

The previous prime is 681996619. The next prime is 681996647. The reversal of 681996628 is 826699186.

It can be written as a sum of positive squares in 2 ways, for example, as 197908624 + 484088004 = 14068^2 + 22002^2 .

It is a hoax number, since the sum of its digits (55) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 34803 + ... + 50746.

Almost surely, 2^681996628 is an apocalyptic number.

It is an amenable number.

681996628 is a deficient number, since it is larger than the sum of its proper divisors (512110272).

681996628 is a wasteful number, since it uses less digits than its factorization.

681996628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87546 (or 87544 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 55.

The square root of 681996628 is about 26115.0651540447. The cubic root of 681996628 is about 880.2257633566.

The spelling of 681996628 in words is "six hundred eighty-one million, nine hundred ninety-six thousand, six hundred twenty-eight".