655663680 has 448 divisors, whose sum is σ = 2724180480. Its totient is φ = 145317888.

The previous prime is 655663663. The next prime is 655663681. The reversal of 655663680 is 86366556.

655663680 is a `hidden beast` number, since 6 + 5 + 5 + 6 + 636 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×655663680² = 859789722542284800, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (655663681) 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, 2237614 + ... + 2237906.

It is an arithmetic number, because the mean of its divisors is an integer number (6080760).

Almost surely, 2^655663680 is an apocalyptic number.

655663680 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 655663680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1362090240).

655663680 is an abundant number, since it is smaller than the sum of its proper divisors (2068516800).

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

655663680 is a wasteful number, since it uses less digits than its factorization.

655663680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363 (or 347 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The square root of 655663680 is about 25605.9305630551. The cubic root of 655663680 is about 868.7477823382.

The spelling of 655663680 in words is "six hundred fifty-five million, six hundred sixty-three thousand, six hundred eighty".