55122221 has 8 divisors (see below), whose sum is σ = 68723904. Its totient is φ = 42952320.

The previous prime is 55122217. The next prime is 55122241. The reversal of 55122221 is 12222155.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55122221 - 2² = 55122217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 55122193 and 55122202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55122241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 357860 + ... + 358013.

It is an arithmetic number, because the mean of its divisors is an integer number (8590488).

Almost surely, 2^55122221 is an apocalyptic number.

It is an amenable number.

55122221 is a deficient number, since it is larger than the sum of its proper divisors (13601683).

55122221 is a wasteful number, since it uses less digits than its factorization.

55122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715891.

The product of its digits is 400, while the sum is 20.

The square root of 55122221 is about 7424.4340525053. The cubic root of 55122221 is about 380.5767350360.

Adding to 55122221 its reverse (12222155), we get a palindrome (67344376).

The spelling of 55122221 in words is "fifty-five million, one hundred twenty-two thousand, two hundred twenty-one".