55712221 has 4 divisors (see below), whose sum is σ = 55754172.
Its totient is φ = 55670272.
The previous prime is 55712197. The next prime is 55712227. The reversal of 55712221 is 12221755.
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 48149721 + 7562500 = 6939^2 + 2750^2
It is a cyclic number.
It is not a de Polignac number, because 55712221 - 225 = 22157789 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 (55712227) 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, 18916 + ... + 21661.
It is an arithmetic number, because the mean of its divisors is an integer number (13938543).
Almost surely, 255712221 is an apocalyptic number.
It is an amenable number.
55712221 is a deficient number, since it is larger than the sum of its proper divisors (41951).
55712221 is a wasteful number, since it uses less digits than its factorization.
55712221 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 41950.
The product of its digits is 1400, while the sum is 25.
The square root of 55712221 is about 7464.0619638371.
The cubic root of 55712221 is about 381.9297518916.
Adding to 55712221 its reverse (12221755), we get a palindrome (67933976).
The spelling of 55712221 in words is "fifty-five million, seven hundred twelve thousand, two hundred twenty-one".