2005551 has 6 divisors (see below), whose sum is σ = 2896920. Its totient is φ = 1337028.

The previous prime is 2005547. The next prime is 2005559. The reversal of 2005551 is 1555002.

It is not a de Polignac number, because 2005551 - 2² = 2005547 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2005559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 111411 + ... + 111428.

It is an arithmetic number, because the mean of its divisors is an integer number (482820).

2^2005551 is an apocalyptic number.

2005551 is a deficient number, since it is larger than the sum of its proper divisors (891369).

2005551 is a wasteful number, since it uses less digits than its factorization.

2005551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222845 (or 222842 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 18.

The square root of 2005551 is about 1416.1747773492. The cubic root of 2005551 is about 126.1085610104.

It can be divided in two parts, 2005 and 551, that added together give a triangular number (2556 = T₇₁).

The spelling of 2005551 in words is "two million, five thousand, five hundred fifty-one".