55641221 has 4 divisors (see below), whose sum is σ = 58914252. Its totient is φ = 52368192.

The previous prime is 55641199. The next prime is 55641233. The reversal of 55641221 is 12214655.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39753025 + 15888196 = 6305^2 + 3986^2 .

It is a cyclic number.

It is not a de Polignac number, because 55641221 - 2²² = 51446917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55641241) 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, 1636490 + ... + 1636523.

It is an arithmetic number, because the mean of its divisors is an integer number (14728563).

Almost surely, 2^55641221 is an apocalyptic number.

It is an amenable number.

55641221 is a deficient number, since it is larger than the sum of its proper divisors (3273031).

55641221 is a wasteful number, since it uses less digits than its factorization.

55641221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3273030.

The product of its digits is 2400, while the sum is 26.

The square root of 55641221 is about 7459.3043241310. The cubic root of 55641221 is about 381.7674383726.

Adding to 55641221 its reverse (12214655), we get a palindrome (67855876).

The spelling of 55641221 in words is "fifty-five million, six hundred forty-one thousand, two hundred twenty-one".