421989 has 4 divisors (see below), whose sum is σ = 562656. Its totient is φ = 281324.

The previous prime is 421987. The next prime is 421997. The reversal of 421989 is 989124.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 421989 - 2¹ = 421987 is a prime.

It is a super-2 number, since 2×421989² = 356149432242, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70329 + ... + 70334.

It is an arithmetic number, because the mean of its divisors is an integer number (140664).

2⁴²¹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

421989 is a deficient number, since it is larger than the sum of its proper divisors (140667).

421989 is a wasteful number, since it uses less digits than its factorization.

421989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140666.

The product of its digits is 5184, while the sum is 33.

The square root of 421989 is about 649.6068041516. The cubic root of 421989 is about 75.0067549471.

It can be divided in two parts, 42 and 1989, that multiplied together give a palindrome (83538).

The spelling of 421989 in words is "four hundred twenty-one thousand, nine hundred eighty-nine".