665666356 has 12 divisors (see below), whose sum is σ = 1176450660. Its totient is φ = 329537600.

The previous prime is 665666329. The next prime is 665666357. The reversal of 665666356 is 653666566.

665666356 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 654336400 + 11329956 = 25580^2 + 3366^2 .

It is a super-2 number, since 2×665666356² = 886223395020637472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665666357) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 823441 + ... + 824248.

It is an arithmetic number, because the mean of its divisors is an integer number (98037555).

Almost surely, 2^665666356 is an apocalyptic number.

It is an amenable number.

665666356 is a deficient number, since it is larger than the sum of its proper divisors (510784304).

665666356 is a wasteful number, since it uses less digits than its factorization.

665666356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647794 (or 1647792 counting only the distinct ones).

The product of its digits is 3499200, while the sum is 49.

The square root of 665666356 is about 25800.5107701379. The cubic root of 665666356 is about 873.1433200946.

The spelling of 665666356 in words is "six hundred sixty-five million, six hundred sixty-six thousand, three hundred fifty-six".