55500221 has 16 divisors (see below), whose sum is σ = 64689024. Its totient is φ = 46635264.

The previous prime is 55500217. The next prime is 55500227. The reversal of 55500221 is 12200555.

It is a cyclic number.

It is not a de Polignac number, because 55500221 - 2² = 55500217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 55500193 and 55500202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55500227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159770 + ... + 160116.

It is an arithmetic number, because the mean of its divisors is an integer number (4043064).

Almost surely, 2^55500221 is an apocalyptic number.

It is an amenable number.

55500221 is a deficient number, since it is larger than the sum of its proper divisors (9188803).

55500221 is a wasteful number, since it uses less digits than its factorization.

55500221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740.

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 55500221 is about 7449.8470454097. The cubic root of 55500221 is about 381.4446875933. Note that the first 3 decimals are identical.

Adding to 55500221 its reverse (12200555), we get a palindrome (67700776).

The spelling of 55500221 in words is "fifty-five million, five hundred thousand, two hundred twenty-one".