402001 has 4 divisors (see below), whose sum is σ = 404404. Its totient is φ = 399600.

The previous prime is 401993. The next prime is 402023. The reversal of 402001 is 100204.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 104976 + 297025 = 324^2 + 545^2 .

It is a cyclic number.

It is not a de Polignac number, because 402001 - 2³ = 401993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (402071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 930 + ... + 1291.

It is an arithmetic number, because the mean of its divisors is an integer number (101101).

2⁴⁰²⁰⁰¹ is an apocalyptic number.

It is an amenable number.

402001 is a deficient number, since it is larger than the sum of its proper divisors (2403).

402001 is a wasteful number, since it uses less digits than its factorization.

402001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2402.

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

The square root of 402001 is about 634.0354879658. The cubic root of 402001 is about 73.8032881176.

Adding to 402001 its reverse (100204), we get a palindrome (502205).

The spelling of 402001 in words is "four hundred two thousand, one", and thus it is an iban number.