55572221 has 2 divisors, whose sum is σ = 55572222. Its totient is φ = 55572220.

The previous prime is 55572217. The next prime is 55572239. The reversal of 55572221 is 12227555.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36168196 + 19404025 = 6014^2 + 4405^2 .

It is a cyclic number.

It is not a de Polignac number, because 55572221 - 2² = 55572217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55572521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27786110 + 27786111.

It is an arithmetic number, because the mean of its divisors is an integer number (27786111).

Almost surely, 2^55572221 is an apocalyptic number.

It is an amenable number.

55572221 is a deficient number, since it is larger than the sum of its proper divisors (1).

55572221 is an equidigital number, since it uses as much as digits as its factorization.

55572221 is an evil number, because the sum of its binary digits is even.

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

The square root of 55572221 is about 7454.6777931712. The cubic root of 55572221 is about 381.6095647132.

Adding to 55572221 its reverse (12227555), we get a palindrome (67799776).

The spelling of 55572221 in words is "fifty-five million, five hundred seventy-two thousand, two hundred twenty-one".