421645 has 12 divisors (see below), whose sum is σ = 588924. Its totient is φ = 288960.

The previous prime is 421643. The next prime is 421657. The reversal of 421645 is 546124.

It can be written as a sum of positive squares in 2 ways, for example, as 233289 + 188356 = 483^2 + 434^2 .

It is not a de Polignac number, because 421645 - 2¹ = 421643 is a prime.

It is a super-3 number, since 3×421645³ = 224885844128733375, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 616 + ... + 1105.

It is an arithmetic number, because the mean of its divisors is an integer number (49077).

2⁴²¹⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

421645 is a deficient number, since it is larger than the sum of its proper divisors (167279).

421645 is a wasteful number, since it uses less digits than its factorization.

421645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1740 (or 1733 counting only the distinct ones).

The product of its digits is 960, while the sum is 22.

The square root of 421645 is about 649.3419746174. The cubic root of 421645 is about 74.9863678927.

Adding to 421645 its reverse (546124), we get a palindrome (967769).

The spelling of 421645 in words is "four hundred twenty-one thousand, six hundred forty-five".