2001005551 has 2 divisors, whose sum is σ = 2001005552. Its totient is φ = 2001005550.

The previous prime is 2001005507. The next prime is 2001005593. The reversal of 2001005551 is 1555001002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2001005551 - 2¹¹ = 2001003503 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001005351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000502775 + 1000502776.

It is an arithmetic number, because the mean of its divisors is an integer number (1000502776).

Almost surely, 2^2001005551 is an apocalyptic number.

2001005551 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001005551 is an equidigital number, since it uses as much as digits as its factorization.

2001005551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 250, while the sum is 19.

The square root of 2001005551 is about 44732.6005392041. The cubic root of 2001005551 is about 1260.1321669959.

Adding to 2001005551 its reverse (1555001002), we get a palindrome (3556006553).

The spelling of 2001005551 in words is "two billion, one million, five thousand, five hundred fifty-one".