681795109 has 18 divisors (see below), whose sum is σ = 716991990. Its totient is φ = 648259200.

The previous prime is 681795073. The next prime is 681795157. The reversal of 681795109 is 901597186.

It is a happy number.

It can be written as a sum of positive squares in 9 ways, for example, as 673402500 + 8392609 = 25950^2 + 2897^2 .

It is not a de Polignac number, because 681795109 - 2²¹ = 679697957 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 (681795199) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6254947 + ... + 6255055.

Almost surely, 2^681795109 is an apocalyptic number.

It is an amenable number.

681795109 is a deficient number, since it is larger than the sum of its proper divisors (35196881).

681795109 is an equidigital number, since it uses as much as digits as its factorization.

681795109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 46.

The square root of 681795109 is about 26111.2065787853. The cubic root of 681795109 is about 880.1390573122.

It can be divided in two parts, 6817 and 95109, that added together give a triangular number (101926 = T₄₅₁).

The spelling of 681795109 in words is "six hundred eighty-one million, seven hundred ninety-five thousand, one hundred nine".