551551221221 has 32 divisors (see below), whose sum is σ = 742562623488. Its totient is φ = 395638914240.

The previous prime is 551551221191. The next prime is 551551221229. The reversal of 551551221221 is 122122155155.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-551551221221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551551221229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 383315 + ... + 1118048.

It is an arithmetic number, because the mean of its divisors is an integer number (23205081984).

Almost surely, 2^551551221221 is an apocalyptic number.

It is an amenable number.

551551221221 is a deficient number, since it is larger than the sum of its proper divisors (191011402267).

551551221221 is a wasteful number, since it uses less digits than its factorization.

551551221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1501761.

The product of its digits is 10000, while the sum is 32.

Adding to 551551221221 its reverse (122122155155), we get a palindrome (673673376376).

The spelling of 551551221221 in words is "five hundred fifty-one billion, five hundred fifty-one million, two hundred twenty-one thousand, two hundred twenty-one".