665666144 has 192 divisors, whose sum is σ = 1676505600. Its totient is φ = 255467520.

The previous prime is 665666129. The next prime is 665666171. The reversal of 665666144 is 441666566.

It is a super-2 number, since 2×665666144² = 886222830535657472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 665666095 and 665666104.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3344957 + ... + 3345155.

It is an arithmetic number, because the mean of its divisors is an integer number (8731800).

Almost surely, 2^665666144 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 665666144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838252800).

665666144 is an abundant number, since it is smaller than the sum of its proper divisors (1010839456).

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

665666144 is a wasteful number, since it uses less digits than its factorization.

665666144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293 (or 285 counting only the distinct ones).

The product of its digits is 622080, while the sum is 44.

The square root of 665666144 is about 25800.5066616917. The cubic root of 665666144 is about 873.1432274023.

The spelling of 665666144 in words is "six hundred sixty-five million, six hundred sixty-six thousand, one hundred forty-four".