653666 has 16 divisors (see below), whose sum is σ = 1091328. Its totient is φ = 291600.

The previous prime is 653659. The next prime is 653687. The reversal of 653666 is 666356.

653666 is nontrivially palindromic in base 5.

It is an unprimeable number.

653666 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 401 + ... + 1211.

It is an arithmetic number, because the mean of its divisors is an integer number (68208).

2⁶⁵³⁶⁶⁶ is an apocalyptic number.

653666 is a deficient number, since it is larger than the sum of its proper divisors (437662).

653666 is a wasteful number, since it uses less digits than its factorization.

653666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857.

The product of its digits is 19440, while the sum is 32.

The square root of 653666 is about 808.4961348083. The cubic root of 653666 is about 86.7864582781.

The spelling of 653666 in words is "six hundred fifty-three thousand, six hundred sixty-six".