55370221 has 4 divisors (see below), whose sum is σ = 55457244. Its totient is φ = 55283200.

The previous prime is 55370209. The next prime is 55370239. The reversal of 55370221 is 12207355.

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 37822500 + 17547721 = 6150^2 + 4189^2 .

It is a cyclic number.

It is not a de Polignac number, because 55370221 - 2⁹ = 55369709 is a prime.

It is a super-2 number, since 2×55370221² = 6131722747177682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55370201) 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, 42550 + ... + 43831.

It is an arithmetic number, because the mean of its divisors is an integer number (13864311).

Almost surely, 2^55370221 is an apocalyptic number.

It is an amenable number.

55370221 is a deficient number, since it is larger than the sum of its proper divisors (87023).

55370221 is an equidigital number, since it uses as much as digits as its factorization.

55370221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87022.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 55370221 is about 7441.1169188503. The cubic root of 55370221 is about 381.1466312612.

Adding to 55370221 its reverse (12207355), we get a palindrome (67577576).

The spelling of 55370221 in words is "fifty-five million, three hundred seventy thousand, two hundred twenty-one".