688781913 has 8 divisors (see below), whose sum is σ = 918498528. Its totient is φ = 459126624.

The previous prime is 688781881. The next prime is 688781917. The reversal of 688781913 is 319187886.

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

It is not a de Polignac number, because 688781913 - 2⁵ = 688781881 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (688781917) 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, 30181 + ... + 47837.

It is an arithmetic number, because the mean of its divisors is an integer number (114812316).

Almost surely, 2^688781913 is an apocalyptic number.

It is an amenable number.

688781913 is a deficient number, since it is larger than the sum of its proper divisors (229716615).

688781913 is a wasteful number, since it uses less digits than its factorization.

688781913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30663.

The product of its digits is 580608, while the sum is 51.

The square root of 688781913 is about 26244.6549415305. The cubic root of 688781913 is about 883.1353007435.

The spelling of 688781913 in words is "six hundred eighty-eight million, seven hundred eighty-one thousand, nine hundred thirteen".