653661 has 12 divisors (see below), whose sum is σ = 960960. Its totient is φ = 428040.

The previous prime is 653659. The next prime is 653687. The reversal of 653661 is 166356.

653661 is a `hidden beast` number, since 653 + 6 + 6 + 1 = 666.

It is not a de Polignac number, because 653661 - 2¹ = 653659 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (653621) 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 11 ways as a sum of consecutive naturals, for example, 85 + ... + 1146.

It is an arithmetic number, because the mean of its divisors is an integer number (80080).

2⁶⁵³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

653661 is a deficient number, since it is larger than the sum of its proper divisors (307299).

653661 is a wasteful number, since it uses less digits than its factorization.

653661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1296 (or 1293 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 653661 is about 808.4930426417. The cubic root of 653661 is about 86.7862369961.

The spelling of 653661 in words is "six hundred fifty-three thousand, six hundred sixty-one".