551312221 has 2 divisors, whose sum is σ = 551312222. Its totient is φ = 551312220.

The previous prime is 551312147. The next prime is 551312273. The reversal of 551312221 is 122213155.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 323604121 + 227708100 = 17989^2 + 15090^2 .

It is a cyclic number.

It is not a de Polignac number, because 551312221 - 2¹⁷ = 551181149 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 551312192 and 551312201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (551312291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275656110 + 275656111.

It is an arithmetic number, because the mean of its divisors is an integer number (275656111).

Almost surely, 2^551312221 is an apocalyptic number.

It is an amenable number.

551312221 is a deficient number, since it is larger than the sum of its proper divisors (1).

551312221 is an equidigital number, since it uses as much as digits as its factorization.

551312221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 22.

The square root of 551312221 is about 23480.0387776511. The cubic root of 551312221 is about 819.9723473721.

Adding to 551312221 its reverse (122213155), we get a palindrome (673525376).

The spelling of 551312221 in words is "five hundred fifty-one million, three hundred twelve thousand, two hundred twenty-one".