42001 has 4 divisors (see below), whose sum is σ = 42532. Its totient is φ = 41472.

The previous prime is 41999. The next prime is 42013. The reversal of 42001 is 10024.

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 11025 + 30976 = 105^2 + 176^2 .

It is a 4-Lehmer number, since φ(42001) divides (42001-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 42001 - 2¹ = 41999 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120 + ... + 313.

It is an arithmetic number, because the mean of its divisors is an integer number (10633).

2⁴²⁰⁰¹ is an apocalyptic number.

It is an amenable number.

42001 is a deficient number, since it is larger than the sum of its proper divisors (531).

42001 is an equidigital number, since it uses as much as digits as its factorization.

42001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530.

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

The square root of 42001 is about 204.9414550549. The cubic root of 42001 is about 34.7605423218.

Adding to 42001 its reverse (10024), we get a palindrome (52025).

The spelling of 42001 in words is "forty-two thousand, one", and thus it is an iban number.