681659497 has 4 divisors (see below), whose sum is σ = 681726676. Its totient is φ = 681592320.

The previous prime is 681659483. The next prime is 681659549. The reversal of 681659497 is 794956186.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 528494121 + 153165376 = 22989^2 + 12376^2 .

It is a cyclic number.

It is not a de Polignac number, because 681659497 - 2⁷ = 681659369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681659437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14904 + ... + 39817.

It is an arithmetic number, because the mean of its divisors is an integer number (170431669).

Almost surely, 2^681659497 is an apocalyptic number.

It is an amenable number.

681659497 is a deficient number, since it is larger than the sum of its proper divisors (67179).

681659497 is a wasteful number, since it uses less digits than its factorization.

681659497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67178.

The product of its digits is 3265920, while the sum is 55.

The square root of 681659497 is about 26108.6096336055. The cubic root of 681659497 is about 880.0806989527.

The spelling of 681659497 in words is "six hundred eighty-one million, six hundred fifty-nine thousand, four hundred ninety-seven".