401645 has 4 divisors (see below), whose sum is σ = 481980. Its totient is φ = 321312.

The previous prime is 401629. The next prime is 401651. The reversal of 401645 is 546104.

It is a happy number.

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 244036 + 157609 = 494^2 + 397^2 .

It is a cyclic number.

It is not a de Polignac number, because 401645 - 2⁴ = 401629 is a prime.

It is a super-3 number, since 3×401645³ = 194378555044233375, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40160 + ... + 40169.

It is an arithmetic number, because the mean of its divisors is an integer number (120495).

2⁴⁰¹⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

401645 is a deficient number, since it is larger than the sum of its proper divisors (80335).

401645 is an equidigital number, since it uses as much as digits as its factorization.

401645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80334.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 401645 is about 633.7546844008. The cubic root of 401645 is about 73.7814956924.

Adding to 401645 its reverse (546104), we get a palindrome (947749).

The spelling of 401645 in words is "four hundred one thousand, six hundred forty-five".