655568640 has 180 divisors, whose sum is σ = 2346115464. Its totient is φ = 174790656.

The previous prime is 655568633. The next prime is 655568659. The reversal of 655568640 is 46865556.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (180).

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 polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 100519 + ... + 106841.

Almost surely, 2^655568640 is an apocalyptic number.

655568640 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 655568640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1173057732).

655568640 is an abundant number, since it is smaller than the sum of its proper divisors (1690546824).

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

655568640 is an equidigital number, since it uses as much as digits as its factorization.

655568640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6356 (or 6333 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 45.

The square root of 655568640 is about 25604.0746757230. The cubic root of 655568640 is about 868.7058046285.

The spelling of 655568640 in words is "six hundred fifty-five million, five hundred sixty-eight thousand, six hundred forty".