681566420 has 24 divisors (see below), whose sum is σ = 1454755848. Its totient is φ = 268156800.

The previous prime is 681566387. The next prime is 681566449. The reversal of 681566420 is 24665186.

681566420 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 7333264 + 674233156 = 2708^2 + 25966^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 278111 + ... + 280550.

It is an arithmetic number, because the mean of its divisors is an integer number (60614827).

Almost surely, 2^681566420 is an apocalyptic number.

It is an amenable number.

681566420 is an abundant number, since it is smaller than the sum of its proper divisors (773189428).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

681566420 is a wasteful number, since it uses less digits than its factorization.

681566420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 558731 (or 558729 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 681566420 is about 26106.8270764565. The cubic root of 681566420 is about 880.0406403407.

The spelling of 681566420 in words is "six hundred eighty-one million, five hundred sixty-six thousand, four hundred twenty".