5551221555 has 48 divisors (see below), whose sum is σ = 10780589664. Its totient is φ = 2618749440.

The previous prime is 5551221541. The next prime is 5551221581.

5551221555 is a `hidden beast` number, since 55 + 51 + 2 + 2 + 1 + 555 = 666.

5551221555 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 5551221555 - 2¹⁰ = 5551220531 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 133234 + ... + 169863.

It is an arithmetic number, because the mean of its divisors is an integer number (224595618).

Almost surely, 2^5551221555 is an apocalyptic number.

5551221555 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

5551221555 is a deficient number, since it is larger than the sum of its proper divisors (5229368109).

5551221555 is a wasteful number, since it uses less digits than its factorization.

5551221555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303156 (or 303153 counting only the distinct ones).

The product of its digits is 62500, while the sum is 36.

The square root of 5551221555 is about 74506.5202180319. The cubic root of 5551221555 is about 1770.6369392064.

The spelling of 5551221555 in words is "five billion, five hundred fifty-one million, two hundred twenty-one thousand, five hundred fifty-five".