1689421 has 4 divisors (see below), whose sum is σ = 1695232. Its totient is φ = 1683612.

The previous prime is 1689397. The next prime is 1689431. The reversal of 1689421 is 1249861.

It is a happy number.

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 1689421 - 2⁹ = 1688909 is a prime.

It is a super-3 number, since 3×1689421³ = 14465548961333296383, which contains 333 as substring.

It is a Duffinian number.

1689421 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1689431) 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, 2445 + ... + 3058.

It is an arithmetic number, because the mean of its divisors is an integer number (423808).

2^1689421 is an apocalyptic number.

It is an amenable number.

1689421 is a deficient number, since it is larger than the sum of its proper divisors (5811).

1689421 is an equidigital number, since it uses as much as digits as its factorization.

1689421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5810.

The product of its digits is 3456, while the sum is 31.

The square root of 1689421 is about 1299.7772886152. Note that the first 3 decimals coincide. The cubic root of 1689421 is about 119.1002380241.

The spelling of 1689421 in words is "one million, six hundred eighty-nine thousand, four hundred twenty-one".