681661289707 has 4 divisors (see below), whose sum is σ = 681673932016. Its totient is φ = 681648647400.

The previous prime is 681661289689. The next prime is 681661289711. The reversal of 681661289707 is 707982166186.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681661289707 is a prime.

It is a super-2 number, since 2×681661289707² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681661289807) 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, 6239928 + ... + 6348229.

It is an arithmetic number, because the mean of its divisors is an integer number (170418483004).

Almost surely, 2^681661289707 is an apocalyptic number.

681661289707 is a deficient number, since it is larger than the sum of its proper divisors (12642309).

681661289707 is a wasteful number, since it uses less digits than its factorization.

681661289707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12642308.

The product of its (nonzero) digits is 12192768, while the sum is 61.

The spelling of 681661289707 in words is "six hundred eighty-one billion, six hundred sixty-one million, two hundred eighty-nine thousand, seven hundred seven".