55660221 has 12 divisors (see below), whose sum is σ = 82992000. Its totient is φ = 35909640.

The previous prime is 55660219. The next prime is 55660259. The reversal of 55660221 is 12206655.

55660221 is a `hidden beast` number, since 5 + 56 + 602 + 2 + 1 = 666.

It is not a de Polignac number, because 55660221 - 2¹ = 55660219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55660201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99471 + ... + 100028.

It is an arithmetic number, because the mean of its divisors is an integer number (6916000).

Almost surely, 2^55660221 is an apocalyptic number.

It is an amenable number.

55660221 is a deficient number, since it is larger than the sum of its proper divisors (27331779).

55660221 is a wasteful number, since it uses less digits than its factorization.

55660221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199536 (or 199533 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 55660221 is about 7460.5777926378. The cubic root of 55660221 is about 381.8108879095.

Adding to 55660221 its reverse (12206655), we get a palindrome (67866876).

The spelling of 55660221 in words is "fifty-five million, six hundred sixty thousand, two hundred twenty-one".