681847645 has 8 divisors (see below), whose sum is σ = 866347704. Its totient is φ = 513391104.

The previous prime is 681847643. The next prime is 681847669. The reversal of 681847645 is 546748186.

It can be written as a sum of positive squares in 4 ways, for example, as 360506169 + 321341476 = 18987^2 + 17926^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 681847645 - 2¹ = 681847643 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681847643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4010784 + ... + 4010953.

It is an arithmetic number, because the mean of its divisors is an integer number (108293463).

Almost surely, 2^681847645 is an apocalyptic number.

It is an amenable number.

681847645 is a deficient number, since it is larger than the sum of its proper divisors (184500059).

681847645 is a wasteful number, since it uses less digits than its factorization.

681847645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8021759.

The product of its digits is 1290240, while the sum is 49.

The square root of 681847645 is about 26112.2125642390. The cubic root of 681847645 is about 880.1616632229.

The spelling of 681847645 in words is "six hundred eighty-one million, eight hundred forty-seven thousand, six hundred forty-five".