4001551 has 2 divisors, whose sum is σ = 4001552. Its totient is φ = 4001550.

The previous prime is 4001549. The next prime is 4001561. The reversal of 4001551 is 1551004.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 4001551 - 2¹ = 4001549 is a prime.

Together with 4001549, 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 (4001521) 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 as a sum of consecutive naturals, namely, 2000775 + 2000776.

It is an arithmetic number, because the mean of its divisors is an integer number (2000776).

Almost surely, 2^4001551 is an apocalyptic number.

4001551 is a deficient number, since it is larger than the sum of its proper divisors (1).

4001551 is an equidigital number, since it uses as much as digits as its factorization.

4001551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 4001551 is about 2000.3877124198. The cubic root of 4001551 is about 158.7606197041.

Adding to 4001551 its reverse (1551004), we get a palindrome (5552555).

The spelling of 4001551 in words is "four million, one thousand, five hundred fifty-one".