665018449920 has 720 divisors, whose sum is σ = 2608905394368. Its totient is φ = 161163509760.

The previous prime is 665018449897. The next prime is 665018449943. The reversal of 665018449920 is 29944810566.

665018449920 is a `hidden beast` number, since 6 + 6 + 50 + 1 + 84 + 499 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (665018449897) and next prime (665018449943).

It is a tau number, because it is divible by the number of its divisors (720).

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 218970642 + ... + 218973678.

Almost surely, 2^665018449920 is an apocalyptic number.

665018449920 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 665018449920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1304452697184).

665018449920 is an abundant number, since it is smaller than the sum of its proper divisors (1943886944448).

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

665018449920 is an equidigital number, since it uses as much as digits as its factorization.

665018449920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3096 (or 3058 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 665018449920 in words is "six hundred sixty-five billion, eighteen million, four hundred forty-nine thousand, nine hundred twenty".