657608640 has 448 divisors, whose sum is σ = 2457907200. Its totient is φ = 147603456.

The previous prime is 657608621. The next prime is 657608641. The reversal of 657608640 is 46806756.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 657608592 and 657608601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (657608641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8324121 + ... + 8324199.

It is an arithmetic number, because the mean of its divisors is an integer number (5486400).

Almost surely, 2^657608640 is an apocalyptic number.

657608640 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 657608640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1228953600).

657608640 is an abundant number, since it is smaller than the sum of its proper divisors (1800298560).

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

657608640 is a wasteful number, since it uses less digits than its factorization.

657608640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 42.

The square root of 657608640 is about 25643.8811415121. The cubic root of 657608640 is about 869.6059518193.

The spelling of 657608640 in words is "six hundred fifty-seven million, six hundred eight thousand, six hundred forty".