55061221 has 4 divisors (see below), whose sum is σ = 57959200. Its totient is φ = 52163244.

The previous prime is 55061207. The next prime is 55061243. The reversal of 55061221 is 12216055.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12216055 = 5 ⋅2443211.

It is a cyclic number.

It is not a de Polignac number, because 55061221 - 2⁵ = 55061189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 55061192 and 55061201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55061021) 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, 1448961 + ... + 1448998.

It is an arithmetic number, because the mean of its divisors is an integer number (14489800).

Almost surely, 2^55061221 is an apocalyptic number.

It is an amenable number.

55061221 is a deficient number, since it is larger than the sum of its proper divisors (2897979).

55061221 is a wasteful number, since it uses less digits than its factorization.

55061221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2897978.

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 55061221 is about 7420.3248581177. The cubic root of 55061221 is about 380.4362971192.

Adding to 55061221 its reverse (12216055), we get a palindrome (67277276).

The spelling of 55061221 in words is "fifty-five million, sixty-one thousand, two hundred twenty-one".