4002001 has 2 divisors, whose sum is σ = 4002002. Its totient is φ = 4002000.

The previous prime is 4001999. The next prime is 4002013. The reversal of 4002001 is 1002004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3097600 + 904401 = 1760^2 + 951^2 .

It is a cyclic number.

It is not a de Polignac number, because 4002001 - 2¹ = 4001999 is a prime.

Together with 4001999, it forms a pair of twin primes.

It is the 2001-st Hogben number.

It is not a weakly prime, because it can be changed into another prime (4002041) by changing a digit.

It is a nontrivial repunit in base 2000.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2001000 + 2001001.

It is an arithmetic number, because the mean of its divisors is an integer number (2001001).

Almost surely, 2^4002001 is an apocalyptic number.

It is an amenable number.

4002001 is a deficient number, since it is larger than the sum of its proper divisors (1).

4002001 is an equidigital number, since it uses as much as digits as its factorization.

4002001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 4002001 is about 2000.5001874531. The cubic root of 4002001 is about 158.7665706967.

Adding to 4002001 its reverse (1002004), we get a palindrome (5004005).

It can be divided in two parts, 400 and 2001, that added together give a 4-th power (2401 = 7⁴).

The spelling of 4002001 in words is "four million, two thousand, one".