688571640 has 96 divisors (see below), whose sum is σ = 2263107600. Its totient is φ = 181547520.

The previous prime is 688571629. The next prime is 688571683. The reversal of 688571640 is 46175886.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21295 + ... + 42785.

Almost surely, 2^688571640 is an apocalyptic number.

688571640 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 688571640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131553800).

688571640 is an abundant number, since it is smaller than the sum of its proper divisors (1574535960).

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

688571640 is a wasteful number, since it uses less digits than its factorization.

688571640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21597 (or 21590 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The square root of 688571640 is about 26240.6486200322. The cubic root of 688571640 is about 883.0454230402.

The spelling of 688571640 in words is "six hundred eighty-eight million, five hundred seventy-one thousand, six hundred forty".