665772768 has 216 divisors, whose sum is σ = 2122094520. Its totient is φ = 197406720.

The previous prime is 665772761. The next prime is 665772773. The reversal of 665772768 is 867277566.

665772768 is a `hidden beast` number, since 6 + 6 + 577 + 2 + 7 + 68 = 666.

It is a super-2 number, since 2×665772768² = 886506757220763648, which contains 22 as substring.

Its product of digits (5927040) is a multiple of the sum of its prime factors (490).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665772761) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1581198 + ... + 1581618.

Almost surely, 2^665772768 is an apocalyptic number.

665772768 is a gapful number since it is divisible by the number (68) 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 665772768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1061047260).

665772768 is an abundant number, since it is smaller than the sum of its proper divisors (1456321752).

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

665772768 is a wasteful number, since it uses less digits than its factorization.

665772768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490 (or 462 counting only the distinct ones).

The product of its digits is 5927040, while the sum is 54.

The square root of 665772768 is about 25802.5728949653. The cubic root of 665772768 is about 873.1898438902.

The spelling of 665772768 in words is "six hundred sixty-five million, seven hundred seventy-two thousand, seven hundred sixty-eight".