55736221 has 2 divisors, whose sum is σ = 55736222. Its totient is φ = 55736220.

The previous prime is 55736209. The next prime is 55736227. The reversal of 55736221 is 12263755.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52272900 + 3463321 = 7230^2 + 1861^2 .

It is a cyclic number.

It is not a de Polignac number, because 55736221 - 2⁵ = 55736189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55736227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27868110 + 27868111.

It is an arithmetic number, because the mean of its divisors is an integer number (27868111).

Almost surely, 2^55736221 is an apocalyptic number.

It is an amenable number.

55736221 is a deficient number, since it is larger than the sum of its proper divisors (1).

55736221 is an equidigital number, since it uses as much as digits as its factorization.

55736221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12600, while the sum is 31.

The square root of 55736221 is about 7465.6694944258. The cubic root of 55736221 is about 381.9845872458.

Adding to 55736221 its reverse (12263755), we get a palindrome (67999976).

The spelling of 55736221 in words is "fifty-five million, seven hundred thirty-six thousand, two hundred twenty-one".