665749056 has 336 divisors, whose sum is σ = 2265436160. Its totient is φ = 168376320.

The previous prime is 665749043. The next prime is 665749057. The reversal of 665749056 is 650947566.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×665749056² = 886443611129782272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a junction number, because it is equal to n+sod(n) for n = 665748996 and 665749014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665749057) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 21475761 + ... + 21475791.

Almost surely, 2^665749056 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 665749056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1132718080).

665749056 is an abundant number, since it is smaller than the sum of its proper divisors (1599687104).

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

665749056 is a wasteful number, since it uses less digits than its factorization.

665749056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 91 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 48.

The square root of 665749056 is about 25802.1134018127. The cubic root of 665749056 is about 873.1794773285.

The spelling of 665749056 in words is "six hundred sixty-five million, seven hundred forty-nine thousand, fifty-six".