665407433844 has 96 divisors (see below), whose sum is σ = 1759839594240. Its totient is φ = 217384280064.

The previous prime is 665407433833. The next prime is 665407433857. The reversal of 665407433844 is 448334704566.

665407433844 is a `hidden beast` number, since 66 + 540 + 7 + 4 + 3 + 38 + 4 + 4 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 770692 + ... + 1387364.

It is an arithmetic number, because the mean of its divisors is an integer number (18331662440).

Almost surely, 2^665407433844 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 665407433844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (879919797120).

665407433844 is an abundant number, since it is smaller than the sum of its proper divisors (1094432160396).

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

665407433844 is a wasteful number, since it uses less digits than its factorization.

665407433844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 616886 (or 616878 counting only the distinct ones).

The product of its (nonzero) digits is 23224320, while the sum is 54.

The spelling of 665407433844 in words is "six hundred sixty-five billion, four hundred seven million, four hundred thirty-three thousand, eight hundred forty-four".