681708913 has 4 divisors (see below), whose sum is σ = 683673840. Its totient is φ = 679743988.

The previous prime is 681708889. The next prime is 681708943. The reversal of 681708913 is 319807186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 681708913 - 2²¹ = 679611761 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 681708913.

It is not an unprimeable number, because it can be changed into a prime (681708943) 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, 981943 + ... + 982636.

It is an arithmetic number, because the mean of its divisors is an integer number (170918460).

Almost surely, 2^681708913 is an apocalyptic number.

It is an amenable number.

681708913 is a deficient number, since it is larger than the sum of its proper divisors (1964927).

681708913 is a wasteful number, since it uses less digits than its factorization.

681708913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1964926.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 681708913 is about 26109.5559709467. Note that the first 3 decimals coincide. The cubic root of 681708913 is about 880.1019651993.

The spelling of 681708913 in words is "six hundred eighty-one million, seven hundred eight thousand, nine hundred thirteen".