55225721 has 4 divisors (see below), whose sum is σ = 55281252. Its totient is φ = 55170192.

The previous prime is 55225697. The next prime is 55225733. The reversal of 55225721 is 12752255.

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 20839225 + 34386496 = 4565^2 + 5864^2 .

It is a cyclic number.

It is not a de Polignac number, because 55225721 - 2¹⁴ = 55209337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55221721) 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, 26246 + ... + 28271.

It is an arithmetic number, because the mean of its divisors is an integer number (13820313).

Almost surely, 2^55225721 is an apocalyptic number.

It is an amenable number.

55225721 is a deficient number, since it is larger than the sum of its proper divisors (55531).

55225721 is a wasteful number, since it uses less digits than its factorization.

55225721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55530.

The product of its digits is 7000, while the sum is 29.

The square root of 55225721 is about 7431.4010119223. The cubic root of 55225721 is about 380.8147821959.

Adding to 55225721 its reverse (12752255), we get a palindrome (67977976).

The spelling of 55225721 in words is "fifty-five million, two hundred twenty-five thousand, seven hundred twenty-one".