1001551 has 2 divisors, whose sum is σ = 1001552. Its totient is φ = 1001550.

The previous prime is 1001549. The next prime is 1001563. The reversal of 1001551 is 1551001.

1001551 is nontrivially palindromic in base 16.

It is a weak prime.

It is an emirp because it is prime and its reverse (1551001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1001551 - 2¹ = 1001549 is a prime.

Together with 1001549, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500775 + 500776.

It is an arithmetic number, because the mean of its divisors is an integer number (500776).

2^1001551 is an apocalyptic number.

1001551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001551 is an equidigital number, since it uses as much as digits as its factorization.

1001551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25, while the sum is 13.

The square root of 1001551 is about 1000.7751995328. The cubic root of 1001551 is about 100.0516732941.

Adding to 1001551 its reverse (1551001), we get a palindrome (2552552).

The spelling of 1001551 in words is "one million, one thousand, five hundred fifty-one".