665761824 has 432 divisors, whose sum is σ = 2509678080. Its totient is φ = 165473280.

The previous prime is 665761771. The next prime is 665761847. The reversal of 665761824 is 428167566.

665761824 is a `hidden beast` number, since 6 + 6 + 5 + 7 + 618 + 24 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 665761824.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3485569 + ... + 3485759.

It is an arithmetic number, because the mean of its divisors is an integer number (5809440).

Almost surely, 2^665761824 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665761824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1254839040).

665761824 is an abundant number, since it is smaller than the sum of its proper divisors (1843916256).

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

665761824 is a wasteful number, since it uses less digits than its factorization.

665761824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253 (or 235 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 665761824 is about 25802.3608222193. The cubic root of 665761824 is about 873.1850593538.

The spelling of 665761824 in words is "six hundred sixty-five million, seven hundred sixty-one thousand, eight hundred twenty-four".