688718940 has 288 divisors, whose sum is σ = 2471325696. Its totient is φ = 140175360.

The previous prime is 688718903. The next prime is 688718959. The reversal of 688718940 is 49817886.

688718940 = T₃₈₄₅ + T₃₈₄₆ + ... + T₃₉₃₅.

688718940 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2200224 + ... + 2200536.

It is an arithmetic number, because the mean of its divisors is an integer number (8580992).

Almost surely, 2^688718940 is an apocalyptic number.

688718940 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688718940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1235662848).

688718940 is an abundant number, since it is smaller than the sum of its proper divisors (1782606756).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688718940 is a wasteful number, since it uses less digits than its factorization.

688718940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 374 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 51.

The square root of 688718940 is about 26243.4551841026. The cubic root of 688718940 is about 883.1083858990.

The spelling of 688718940 in words is "six hundred eighty-eight million, seven hundred eighteen thousand, nine hundred forty".