55116221 has 2 divisors, whose sum is σ = 55116222. Its totient is φ = 55116220.

The previous prime is 55116203. The next prime is 55116253. The reversal of 55116221 is 12261155.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42055225 + 13060996 = 6485^2 + 3614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55116221 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55116521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27558110 + 27558111.

It is an arithmetic number, because the mean of its divisors is an integer number (27558111).

Almost surely, 2^55116221 is an apocalyptic number.

It is an amenable number.

55116221 is a deficient number, since it is larger than the sum of its proper divisors (1).

55116221 is an equidigital number, since it uses as much as digits as its factorization.

55116221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 23.

The square root of 55116221 is about 7424.0299703059. The cubic root of 55116221 is about 380.5629260661.

Adding to 55116221 its reverse (12261155), we get a palindrome (67377376).

The spelling of 55116221 in words is "fifty-five million, one hundred sixteen thousand, two hundred twenty-one".