551205521 has 2 divisors, whose sum is σ = 551205522. Its totient is φ = 551205520.

The previous prime is 551205503. The next prime is 551205533. The reversal of 551205521 is 125502155.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 296356225 + 254849296 = 17215^2 + 15964^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-551205521 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (551205121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275602760 + 275602761.

It is an arithmetic number, because the mean of its divisors is an integer number (275602761).

Almost surely, 2^551205521 is an apocalyptic number.

It is an amenable number.

551205521 is a deficient number, since it is larger than the sum of its proper divisors (1).

551205521 is an equidigital number, since it uses as much as digits as its factorization.

551205521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2500, while the sum is 26.

The square root of 551205521 is about 23477.7665249487. The cubic root of 551205521 is about 819.9194452892.

Adding to 551205521 its reverse (125502155), we get a palindrome (676707676).

The spelling of 551205521 in words is "five hundred fifty-one million, two hundred five thousand, five hundred twenty-one".